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Sample records for ion-beam assisted silicon

  1. Synthesis of silicon oxynitride by ion beam sputtering and the effects of nitrogen ion-assisted bombardment

    NASA Astrophysics Data System (ADS)

    Lambrinos, M. F.; Valizadeh, R.; Colligon, J. S.

    1997-05-01

    Thin silicon oxynitride (SiO xN y) films were synthesised without substrate heating by means of N 2+ ion-beam sputtering of a silicon nitride target at an energy of 1000 eV in a N 2 and O 2 ambient with and without 200 eV N 2+ ion assistance. Unassisted films were deposited in a controlled O 2 partial pressure ranging from ambient to 5.0 × 10 -3 Pa whereas assisted films were deposited at a fixed O 2 partial pressure of 1.0 × 10 -3 Pa. The O/(O+N) atomic fraction and the SiO xN y asymmetric stretch mode IR absorption peak wavenumber of unassisted films increased almost linearly with increasing O 2 partial pressure, from 0.2 to 1.0 and 860 cm -1 to 1050 cm -1, respectively, while their refractive indices decreased from 1.92 to 1.46. The behaviour of the SiO xN y film refractive index with the SiO 2 fraction has been compared to that predicted by Drude, Lorentz-Lorenz and Bruggeman models under the assumption that the film is a mixture of SiO 2 and Si 3N 4 phases. For a fixed O 2 partial pressure, the O content of the N 2+ ion-assisted films increased with an increase in the N + ion to Si atom arrival ratio from 0 to 3. This increase in O content correlate with changes in the film refractive index and SiO xN y asymmetric stretch mode absorption peak position, from 1.56 to 1.43 and 1014 cm -1 to 1054 cm -1, respectively, indicating that the O/N atomic ratio increases with increasing N + ion to Si atom ratio until film properties consistent with stoichiometric SiO 2 are obtained.

  2. Physical Sputtering vs. Gas Assisted Etching of Silicon Dioxide with a Gallium Focused Ion Beam: Elucidating Experiments via Monte Carlo Simulations

    NASA Astrophysics Data System (ADS)

    Timilsina, Rajendra; Tan, Shida; Livengood, Richard; Rack, Philip

    2015-03-01

    In order to increase ion beam nanomachining precision and improve imaging resolution, fine tuning of the ion beam profile is absolutely necessary. To understand the effects of ion beam tails, experiments and Monte Carlo simulations were conducted with a 40 keV gallium beam with and without gas assisted chemical etching. A gallium ion beam was scanned in an area of 25x25 nm2 on a silicon dioxide film with and without a localized XeF2 gas at 1pA current. Four different ion doses (0.23, 0.9, 1.8 and 3.6 nC/ μm2) were experimentally considered to study the sputtered and etched via profiles. Monte Carlo simulations using EnvizION program was performed to elucidate the sputtered and gas-assisted etch process. New features including gas-assisted etching by secondary electrons and a binary collision model to dissociate the precursor molecules were introduced. Sputtered via and gas assisted etching (XeF2 precursor gas) via profiles with various gas-assist pressures were studied to understand the experimental temporal behavior. Various contributions including sputtering from primary, forward scattered, backscattered ions as well as etching by recoiled atoms and secondary electrons will be discussed.

  3. Synthesis and corrosion properties of silicon nitride films by ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Baba, K.; Hatada, R.; Emmerich, R.; Enders, B.; Wolf, G. K.

    1995-12-01

    Silicon nitride films SiN x were deposited on 316L austenitic stainless steel substrates by silicon evaporation and simultaneous nitrogen ion irradiation with an acceleration voltage of 2 kV. In order to study the influence of the nitrogen content on changes in stoichiometry, structure, morphology, thermal oxidation behaviour and corrosion behaviour, the atom to ion transport ratio was systematically varied. The changes of binding states and the stoichiometry were evaluated with XPS and AES analysis. A maximum nitrogen content was reached with a {Si}/{N} transport ratio lower than 2. The films are chemically inert when exposed to laboratory atmosphere up to a temperature of more than 1000°C. XRD and SEM measurements show amorphous and featureless films for transport ratios {Si}/{N} from 1 up to 10. The variation of the corrosion behaviour of coated stainless steel substrates in sulphuric acid and hydrochloric acid shows a minimum at medium transport ratios. This goes parallel with changes in porosity and adhesion. Additional investigations showed that titanium implantation as an intermediate step improves the corrosion resistance considerably.

  4. Ion beam figuring of silicon aspheres

    NASA Astrophysics Data System (ADS)

    Demmler, Marcel; Zeuner, Michael; Luca, Alfonz; Dunger, Thoralf; Rost, Dirk; Kiontke, Sven; Krüger, Marcus

    2011-03-01

    Silicon lenses are widely used for infrared applications. Especially for portable devices the size and weight of the optical system are very important factors. The use of aspherical silicon lenses instead of spherical silicon lenses results in a significant reduction of weight and size. The manufacture of silicon lenses is more challenging than the manufacture of standard glass lenses. Typically conventional methods like diamond turning, grinding and polishing are used. However, due to the high hardness of silicon, diamond turning is very difficult and requires a lot of experience. To achieve surfaces of a high quality a polishing step is mandatory within the manufacturing process. Nevertheless, the required surface form accuracy cannot be achieved through the use of conventional polishing methods because of the unpredictable behavior of the polishing tools, which leads to an unstable removal rate. To overcome these disadvantages a method called Ion Beam Figuring can be used to manufacture silicon lenses with high surface form accuracies. The general advantage of the Ion Beam Figuring technology is a contactless polishing process without any aging effects of the tool. Due to this an excellent stability of the removal rate without any mechanical surface damage is achieved. The related physical process - called sputtering - can be applied to any material and is therefore also applicable to materials of high hardness like Silicon (SiC, WC). The process is realized through the commercially available ion beam figuring system IonScan 3D. During the process, the substrate is moved in front of a focused broad ion beam. The local milling rate is controlled via a modulated velocity profile, which is calculated specifically for each surface topology in order to mill the material at the associated positions to the target geometry. The authors will present aspherical silicon lenses with very high surface form accuracies compared to conventionally manufactured lenses.

  5. Metal assisted focused-ion beam nanopatterning

    NASA Astrophysics Data System (ADS)

    Kannegulla, Akash; Cheng, Li-Jing

    2016-09-01

    Focused-ion beam milling is a versatile technique for maskless nanofabrication. However, the nonuniform ion beam profile and material redeposition tend to disfigure the surface morphology near the milling areas and degrade the fidelity of nanoscale pattern transfer, limiting the applicability of the technique. The ion-beam induced damage can deteriorate the performance of photonic devices and hinders the precision of template fabrication for nanoimprint lithography. To solve the issue, we present a metal assisted focused-ion beam (MAFIB) process in which a removable sacrificial aluminum layer is utilized to protect the working material. The new technique ensures smooth surfaces and fine milling edges; in addition, it permits direct formation of v-shaped grooves with tunable angles on dielectric substrates or metal films, silver for instance, which are rarely achieved by using traditional nanolithography followed by anisotropic etching processes. MAFIB was successfully demonstrated to directly create nanopatterns on different types of substrates with high fidelity and reproducibility. The technique provides the capability and flexibility necessary to fabricate nanophotonic devices and nanoimprint templates.

  6. Metal assisted focused-ion beam nanopatterning.

    PubMed

    Kannegulla, Akash; Cheng, Li-Jing

    2016-09-01

    Focused-ion beam milling is a versatile technique for maskless nanofabrication. However, the nonuniform ion beam profile and material redeposition tend to disfigure the surface morphology near the milling areas and degrade the fidelity of nanoscale pattern transfer, limiting the applicability of the technique. The ion-beam induced damage can deteriorate the performance of photonic devices and hinders the precision of template fabrication for nanoimprint lithography. To solve the issue, we present a metal assisted focused-ion beam (MAFIB) process in which a removable sacrificial aluminum layer is utilized to protect the working material. The new technique ensures smooth surfaces and fine milling edges; in addition, it permits direct formation of v-shaped grooves with tunable angles on dielectric substrates or metal films, silver for instance, which are rarely achieved by using traditional nanolithography followed by anisotropic etching processes. MAFIB was successfully demonstrated to directly create nanopatterns on different types of substrates with high fidelity and reproducibility. The technique provides the capability and flexibility necessary to fabricate nanophotonic devices and nanoimprint templates. PMID:27479713

  7. Ion-beam-assisted etching of diamond

    NASA Technical Reports Server (NTRS)

    Efremow, N. N.; Geis, M. W.; Flanders, D. C.; Lincoln, G. A.; Economou, N. P.

    1985-01-01

    The high thermal conductivity, low RF loss, and inertness of diamond make it useful in traveling wave tubes operating in excess of 500 GHz. Such use requires the controlled etching of type IIA diamond to produce grating like structures tens of micrometers deep. Previous work on reactive ion etching with O2 gave etching rates on the order of 20 nm/min and poor etch selectivity between the masking material (Ni or Cr) and the diamond. An alternative approach which uses a Xe(+) beam and a reactive gas flux of NO2 in an ion-beam-assisted etching system is reported. An etching rate of 200 nm/min was obtained with an etching rate ratio of 20 between the diamond and an aluminum mask.

  8. Ion beams in silicon processing and characterization

    SciTech Connect

    Chason, E.; Picraux, S.T.; Poate, J.M.; Borland, J.O.; Current, M.I.; Diaz de la Rubia, T.; Eaglesham, D.J.; Holland, O.W.; Law, M.E.; Magee, C.W.; Mayer, J.W.; Melngailis, J.; Tasch, A.F.

    1997-05-01

    General trends in integrated circuit technology toward smaller device dimensions, lower thermal budgets, and simplified processing steps present severe physical and engineering challenges to ion implantation. These challenges, together with the need for physically based models at exceedingly small dimensions, are leading to a new level of understanding of fundamental defect science in Si. In this article, we review the current status and future trends in ion implantation of Si at low and high energies with particular emphasis on areas where recent advances have been made and where further understanding is needed. Particularly interesting are the emerging approaches to defect and dopant distribution modeling, transient enhanced diffusion, high energy implantation and defect accumulation, and metal impurity gettering. Developments in the use of ion beams for analysis indicate much progress has been made in one-dimensional analysis, but that severe challenges for two-dimensional characterization remain. The breadth of ion beams in the semiconductor industry is illustrated by the successful use of focused beams for machining and repair, and the development of ion-based lithographic systems. This suite of ion beam processing, modeling, and analysis techniques will be explored both from the perspective of the emerging science issues and from the technological challenges. {copyright} {ital 1997 American Institute of Physics.}

  9. Deposition of reactively ion beam sputtered silicon nitride coatings

    NASA Technical Reports Server (NTRS)

    Grill, A.

    1982-01-01

    An ion beam source was used to deposit silicon nitride films by reactively sputtering a silicon target with beams of Ar + N2 mixtures. The nitrogen fraction in the sputtering gas was 0.05 to 0.80 at a total pressure of 6 to 2 millionth torr. The ion beam current was 50 mA at 500 V. The composition of the deposited films was investigated by auger electron spectroscopy and the rate of deposition was determined by interferometry. A relatively low rate of deposition of about 2 nm. one-tenth min. was found. AES spectra of films obtained with nitrogen fractions higher than 0.50 were consistent with a silicon to nitrogen ratio corresponding to Si3N4. However the AES spectra also indicated that the sputtered silicon nitride films were contaminated with oxygen and carbon and contained significant amounts of iron, nickel, and chromium, most probably sputtered from the holder of the substrate and target.

  10. Dual ion beam assisted deposition of biaxially textured template layers

    SciTech Connect

    Groves, James R.; Arendt, Paul N.; Hammond, Robert H.

    2005-05-31

    The present invention is directed towards a process and apparatus for epitaxial deposition of a material, e.g., a layer of MgO, onto a substrate such as a flexible metal substrate, using dual ion beams for the ion beam assisted deposition whereby thick layers can be deposited without degradation of the desired properties by the material. The ability to deposit thicker layers without loss of properties provides a significantly broader deposition window for the process.

  11. Chemically assisted ion beam etching of polycrystalline and (100)tungsten

    NASA Technical Reports Server (NTRS)

    Garner, Charles

    1987-01-01

    A chemically assisted ion-beam etching technique is described which employs an ion beam from an electron-bombardment ion source and a directed flux of ClF3 neutrals. This technique enables the etching of tungsten foils and films in excess of 40 microns thick with good anisotropy and pattern definition over areas of 30 sq mm, and with a high degree of selectivity. (100) tungsten foils etched with this process exhibit preferred-orientation etching, while polycrystalline tungsten films exhibit high etch rates. This technique can be used to pattern the dispenser cathode surfaces serving as electron emitters in traveling-wave tubes to a controlled porosity.

  12. Ion beam lithography with gold and silicon ions

    NASA Astrophysics Data System (ADS)

    Seniutinas, Gediminas; Balčytis, Armandas; Nishijima, Yoshiaki; Nadzeyka, Achim; Bauerdick, Sven; Juodkazis, Saulius

    2016-04-01

    Different ion species deliver a different material sputtering yield and implantation depth, thus enabling focused ion beam (FIB) fabrication for diverse applications. Using newly developed FIB milling with double charged hbox {Au}^{2+} and hbox {Si}^{2+} ions, fabrication has been carried out on Au-sputtered films to define arrays of densely packed nanoparticles supporting optical extinction peaks at visible-IR wavelengths determined by the size, shape, and proximity of nanoparticles. Results are qualitatively compared with hbox {Ga}+ milling. A possibility to use such ion implantation to tailor the etching rate of silicon is also demonstrated.

  13. Synthesis of silicon nitride films by ion beam enhanced deposition

    NASA Astrophysics Data System (ADS)

    Xianghuai, Liu; Bin, Xue; Zhihong, Zheng; Zuyao, Zhou; Shichang, Zou

    1989-03-01

    Silicon nitride films with stoichiometric ratio of Si 3N 4 have been synthesized by concurrent electron beam evaporation of silicon and bombardment with nitrogen ions. The results show that the component ratio of nitrogen to silicon in IBED silicon nitride films can be controlled and predicted by the atomic arrival rate ratio of nitrogen to silicon. IR measurement shows that the characteristic absorption peak of IBED Si 3N 4 is located at a wavenumber of 840 cm -1. The refractive index ranges from 2.2 to 2.6. RBS, AES, TEM, SEM, ED and spreading resistance measurement were used for investigation of the depth profiles of composition and structure of silicon nitride films synthesized by IBED. An intermixed layer is formed at the interface by the knock on effect, and a silicon enriched layer is observed at the surface region of the film. Normally the films were found to be amorphous, but electron diffraction patterns taken from deposited layer showed a certain crystallinity. The silicon nitride films prepared by IBED have dramatically less oxygen content than that formed by non-ion-assisted deposition.

  14. Silicon Oxide Deposition into a Hole Using a Focused Ion Beam

    NASA Astrophysics Data System (ADS)

    Nakamura, Hiroko; Komano, Haruki; Norimatu, Kenji; Gomei, Yoshio

    1991-11-01

    Focused ion beam (FIB)-induced deposition of silicon oxide in terms of filling a hole is reported. It was found that a vacant space was formed when an ion beam was simply scanned through the hole area. To investigate the mechanism to form the vacancy, deposition on the sample, which has a step with a height of 0.8 μm, was carried out by using a Si2+ and a Be2+ ion beam. An extruded deposit resembling a pent roof was observed from the step ridge. The mechanism of the pent roof growth on the steplike sample was considered and the vacancy formation in the hole can be explained by the same mechanism. For silicon oxide, the high growth rate of the extruded deposit is thought to be the key to the vacancy formation. A useful way is proposed to fill the hole with silicon oxide with almost no vacancy.

  15. Fabrication of OSOS cells by neutral ion beam sputtering. [Oxide Semiconductor On Silicon solar cells

    NASA Technical Reports Server (NTRS)

    Burk, D. E.; Dubow, J. B.; Sites, J. R.

    1976-01-01

    Oxide semiconductor on silicon (OSOS) solar cells have been fabricated from various indium tin oxide (In2O3)x(SnO2)1-x compositions sputtered onto p-type single crystal silicon substrates with a neutralized argon ion beam. High temperature processing or annealing was not required. The highest efficiency was achieved with x = 0.91 and was 12 percent. The cells are environmentally rugged, chemically stable, and show promise for still higher efficiencies. Moreover, the ion beam sputtering fabrication technique is amenable to low cost, continuous processing.

  16. Ion beam mixing at nickel-silicon interfaces

    SciTech Connect

    Averback, R.S.; Thompson, L.J. Jr.; Moyle, J.; Schalit, M.

    1982-03-01

    Ion-beam mixing at Ni-Si interfaces was studied as a function of dose, temperature, and dose rate. In the temperature range 10--443 K, the thickness of the mixed Ni-Si layer grew proportionally to the square root of dose for 250-keV Ar/sup +/ and 280-keV Kr/sup +/ irradiations. The apparent diffusion coefficient for mixing during irradiation comprises temperature-dependent and independent contributions. The activation enthalpy for the temperature-dependent part is approx.0.09 eV. Varying the dose rate by a factor of approx.20 had little effect upon mixing at either 80 or 368 K. Analysis of these results using chemical rate theory showed that the low activation enthalpy for diffusion was not associated with point-defect motion. More likely the temperature dependence of mixing in Ni-Si is associated with the effect of temperature on compound formation. The results for mixing at 10 K in Ni-Si were compared with those in Ni-Al, at 10 K, to study the effect of crystal structure on displacement mixing.

  17. Structural and composition investigations at delayered locations of low k integrated circuit device by gas-assisted focused ion beam

    SciTech Connect

    Wang, Dandan Kee Tan, Pik; Yamin Huang, Maggie; Lam, Jeffrey; Mai, Zhihong

    2014-05-15

    The authors report a new delayering technique – gas-assisted focused ion beam (FIB) method and its effects on the top layer materials of integrated circuit (IC) device. It demonstrates a highly efficient failure analysis with investigations on the precise location. After removing the dielectric layers under the bombardment of an ion beam, the chemical composition of the top layer was altered with the reduced oxygen content. Further energy-dispersive x-ray spectroscopy and Fourier transform infrared analysis revealed that the oxygen reduction lead to appreciable silicon suboxide formation. Our findings with structural and composition alteration of dielectric layer after FIB delayering open up a new insight avenue for the failure analysis in IC devices.

  18. Method for forming metallic silicide films on silicon substrates by ion beam deposition

    DOEpatents

    Zuhr, Raymond A.; Holland, Orin W.

    1990-01-01

    Metallic silicide films are formed on silicon substrates by contacting the substrates with a low-energy ion beam of metal ions while moderately heating the substrate. The heating of the substrate provides for the diffusion of silicon atoms through the film as it is being formed to the surface of the film for interaction with the metal ions as they contact the diffused silicon. The metallic silicide films provided by the present invention are contaminant free, of uniform stoichiometry, large grain size, and exhibit low resistivity values which are of particular usefulness for integrated circuit production.

  19. Focused ion beam high resolution grayscale lithography for silicon-based nanostructures

    SciTech Connect

    Erdmanis, M. Tittonen, I.

    2014-02-17

    Nanofabrication techniques providing a fine control over the profile of silicon structures are of great importance for nanophotonics, plasmonics, sensing, micro- and nano fluidics, and biomedical applications. We report on the applicability of focused ion beam for the fine grayscale lithography, which yields surface profiles that are customized at nanoscale. The approach is based on a correlation between the ion beam irradiation dose of inorganic resist and the mask etching rate in the reactive ion etching. An exceptional property of this method is the number of gray tones that are not limited by the resist characteristics. We apply the process to fabricate unique periodic nanostructures with a slope angle varying across the structure and a period as small as 200 nm.

  20. Iodine enhanced focused-ion-beam etching of silicon for photonic applications

    SciTech Connect

    Schrauwen, Jonathan; Thourhout, Dries van; Baets, Roel

    2007-11-15

    Focused-ion-beam etching of silicon enables fast and versatile fabrication of micro- and nanophotonic devices. However, large optical losses due to crystal damage and ion implantation make the devices impractical when the optical mode is confined near the etched region. These losses are shown to be reduced by the local implantation and etching of silicon waveguides with iodine gas enhancement, followed by baking at 300 deg. C. The excess optical loss in the silicon waveguides drops from 3500 to 1700 dB/cm when iodine gas is used, and is further reduced to 200 dB/cm after baking at 300 deg. C. We present elemental and chemical surface analyses supporting that this is caused by the desorption of iodine from the silicon surface. Finally we present a model to extract the absorption coefficient from the measurements.

  1. Ion beam assisted deposition of Si-diamond-like carbon coatings on large area substrates

    SciTech Connect

    Fountzoulas, C.G.

    1996-12-31

    Hard, low-friction silicon-containing diamond-like carbon coatings (Si-DLC), were formed by Ar{sup +} ion beam assisted deposition (IBAD), on 5 in. diameter silicon wafers. The diffusion pump oil precursor (tetraphenyl-tetramethyl-trisiloxane: (C{sub 6}H{sub 5}){sub 4}(CH{sub 3}){sub 4}Si{sub 3}O{sub 2}) was evaporated through seven, 3 mm diameter, closely packed apertures (multinozzle/multi-aperture container) arranged in a hexagonal pattern, approximately 5 mm apart according to mathematical model developed at ARL describing the spatial distribution of film deposition from nozzles and apertures onto inclined substrates. The ion energy was kept at 40 keV whereas the ion current density and the oil evaporation temperature were varied to produce hard, lubricious and adherent films. The multinozzle array allowed the relatively uniform ({+-} 20%) coverage of the entire 5 in. substrate. The thickness and the microhardness of the films were measured along the rectilinear surface coordinates of the substrate area. Depending on the deposition parameters the standard deviation of the coating thicknesses and Knoop microhardness varied from 14 to 30% respectively over the substrate. This is a significant improvement from the previously used single nozzle set up where the standard deviation of the coating thickness was 50 to 100% for 2 in. diameter substrates. The Knoop microhardness and the sliding friction coefficient of these coatings ranged from 10,000 to 20,000 MPa and 0.04 and 0.2 respectively. These values are in agreement with the previously reported single nozzle results.

  2. Report on the workshop on Ion Implantation and Ion Beam Assisted Deposition

    NASA Astrophysics Data System (ADS)

    Dearnaley, G.

    1992-03-01

    This workshop was organized by the Corpus Christi Army Depot (CCAD), the major helicopter repair base within AVSCOM. Previous meetings had revealed a strong interest throughout DoD in ion beam technology as a means of extending the service life of military systems by reducing wear, corrosion, fatigue, etc. The workshop opened with an account by Dr. Bruce Sartwell of the successful application of ion implantation to bearings and gears at NRL, and the checkered history of the MANTECH Project at Spire Corporation. Dr. James Hirvonen (AMTL) continued with a summary of successful applications to reduce wear in biomedical components, and he also described the processes of ion beam-assisted deposition (IBAD) for a variety of protective coatings, including diamond-like carbon (DLC).

  3. Ion beam assisted deposition of organic molecules: a physical way to realize OLED structures

    NASA Astrophysics Data System (ADS)

    Moliton, André; Antony, Rémi; Troadec, David; Ratier, Bernard

    2000-05-01

    We demonstrate how the quantum efficiency of an organic light-emitting diode can be improved by a physical way based on the ion beam assisted deposition: the recombination current can be increased by an enhancement of the minority carrier injection while the total current can be decreased by generation of electron traps which reduced the majority current. The quantum efficiency of fluorescence can be also improved by a layer densification with a limitation of the nonradiative centers. As a result, the quantum efficiency of the structure ITO/Helium assisted Alq3/unassisted Alq3/Ca/Al is improved (by around a factor 10) in relation with a virgin structure.

  4. Ion-beam assisted deposition of MgO with in situ RHEED monitoring to control Bi-axial texture

    SciTech Connect

    Arendt, P. N.; Foltyn, S. R.; Jia, Quanxi; DePaula, R. F.; Dowden, P. C.; Kung, H.; Holesinger, T. G.; Stan, L.; Emmert, L. A.; Peterson, E. J.; Groves, J. R.

    2001-01-01

    We have studied the growth of magnesium oxide using ion-beam assisted deposition (IBAD) to achieve (100) oriented, bi-axially textured films with low mosaic spread, for film thicknesses of 10 nm on silicon substrates. We have refined the process by using reflected high-energy electron diffraction (RHEED) to monitor the growth of IBAD MgO films and found that the diffracted intensity can be used to determine (and ultimately control) final in-plane texture of the film. Here we present results on our work to develop the use of real-time RHEED monitoring to deposit well-oriented IBAD MgO films. The results have been corroborated with extensive grazing-incidence X-ray diffraction (GID). Results of these analyses have allowed us to deposit films on metallic substrates with in-plane mosaic spread less than 7{sup o}.

  5. Formation of Diamond-like Carbon Thin Films by Ion Beam Assisted Deposition Method

    NASA Astrophysics Data System (ADS)

    Nakamura, Isao; Takano, Ichiro; Sasaki, Michiko; Takashika, Masaru; Kasiwagi, Tomohumi; Sawada, Yohio

    The mechanical properties of diamond-like carbon (DLC) thin films on SUS304 substrate have been studied. DLC thin films were prepared by the ion beam assisted deposition method. In this method, He+ ion irradiation was carried out in a C2H4 gas atmosphere. He+ ions were accelerated at an energy of 15 keV, and the ion beam current densities were changed from 10 to 100 μA/cm2. Atomic concentration and structure of the films were investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The mechanical properties of hardness and friction coefficient were determined using the Knoop hardness tester and the pin-on-disk tribometer. The DLC thin films had amorphous structure that composed chiefly of graphite and disorder of graphite states. The Knoop hardness of the films increased with increasing He+ ion current density, and the film prepared at a current density of 80 μA/cm2 showed the maximum Knoop hardness value of 890 kgf/cm2. The friction coefficient of the film prepared at a current density of 60 μA/cm2 indicated lower value than that of the other current densities. From these results, it was cleared that the mechanical properties and structure of DLC thin films were greatly affected by the He+ ion beam current density.

  6. Fabrication of Superconducting Mo/Cu Bilayers Using Ion-Beam-Assisted e-Beam Evaporation

    NASA Astrophysics Data System (ADS)

    Jaeckel, Felix T.; Kripps, Kari L.; Morgan, Kelsey M.; Zhang, Shuo; McCammon, Dan

    2016-08-01

    Superconducting/normal metal bilayers with tunable transition temperature are a critical ingredient to the fabrication of high-performance transition edge sensors. Popular material choices include Mo/Au and Mo/Cu, which exhibit good environmental stability and provide low resistivity films to achieve adequate thermal conductivity. The deposition of high-quality Mo films requires sufficient adatom mobility, which can be provided by energetic ions in sputter deposition or by heating the substrate in an e-beam evaporation process. The bilayer T_c depends sensitively on the exact deposition conditions of the Mo layer and the superconducting/normal metal interface. Because the individual contributions (strain, crystalline structure, contamination) are difficult to disentangle and control, reproducibility remains a challenge. Recently, we have demonstrated that low-energy ion-beam-assisted e-beam evaporation offers an alternative route to reliably produce high-quality Mo films without the use of substrate heating. The energy and momentum delivered by the ion beam provides an additional control knob to tune film properties such as resistivity and stress. In this report we describe modifications made to the commercial end-Hall ion source to avoid iron contamination allowing us to produce superconducting Mo films. We show that the ion beam is effective at enhancing the bilayer interface transparency and that bilayers can be further tuned towards reduced T_c and higher conductivity by vacuum annealing.

  7. Selective etching of focused gallium ion beam implanted regions from silicon as a nanofabrication method

    NASA Astrophysics Data System (ADS)

    Han, Zhongmei; Vehkamäki, Marko; Mattinen, Miika; Salmi, Emma; Mizohata, Kenichiro; Leskelä, Markku; Ritala, Mikko

    2015-07-01

    A focused ion beam (FIB) is otherwise an efficient tool for nanofabrication of silicon structures but it suffers from the poor thermal stability of the milled surfaces caused by segregation of implanted gallium leading to severe surface roughening upon already slight annealing. In this paper we show that selective etching with KOH:H2O2 solutions removes the surface layer with high gallium concentration while blocking etching of the surrounding silicon and silicon below the implanted region. This remedies many of the issues associated with gallium FIB nanofabrication of silicon. After the gallium removal sub-nm surface roughness is retained even during annealing. As the etching step is self-limited to a depth of 25-30 nm for 30 keV ions, it is well suited for defining nanoscale features. In what is essentially a reversal of gallium resistless lithography, local implanted areas can be prepared and then subsequently etched away. Nanopore arrays and sub-100 nm trenches can be prepared this way. When protective oxide masks such as Al2O3 grown with atomic layer deposition are used together with FIB milling and KOH:H2O2 etching, ion-induced amorphization can be confined to sidewalls of milled trenches.

  8. Sub-micron resolution of localized ion beam induced charge reduction in silicon detectors damaged by heavy ions

    SciTech Connect

    Auden, Elizabeth C.; Pacheco, Jose L.; Bielejec, Edward; Vizkelethy, Gyorgy; Abraham, John B. S.; Doyle, Barney L.

    2015-12-01

    In this study, displacement damage reduces ion beam induced charge (IBIC) through Shockley-Read-Hall recombination. Closely spaced pulses of 200 keV Si++ ions focused in a 40 nm beam spot are used to create damage cascades within 0.25 μm2 areas. Damaged areas are detected through contrast in IBIC signals generated with focused ion beams of 200 keV Si++ ions and 60 keV Li+ ions. IBIC signal reduction can be resolved over sub-micron regions of a silicon detector damaged by as few as 1000 heavy ions.

  9. Sub-micron resolution of localized ion beam induced charge reduction in silicon detectors damaged by heavy ions

    DOE PAGES

    Auden, Elizabeth C.; Pacheco, Jose L.; Bielejec, Edward; Vizkelethy, Gyorgy; Abraham, John B. S.; Doyle, Barney L.

    2015-12-01

    In this study, displacement damage reduces ion beam induced charge (IBIC) through Shockley-Read-Hall recombination. Closely spaced pulses of 200 keV Si++ ions focused in a 40 nm beam spot are used to create damage cascades within 0.25 μm2 areas. Damaged areas are detected through contrast in IBIC signals generated with focused ion beams of 200 keV Si++ ions and 60 keV Li+ ions. IBIC signal reduction can be resolved over sub-micron regions of a silicon detector damaged by as few as 1000 heavy ions.

  10. Gas-assisted focused-ion-beam lithography of a diamond (100) surface

    NASA Astrophysics Data System (ADS)

    Datta, A.; Wu, Yuh-Renn; Wang, Y. L.

    1999-10-01

    A focused Ga-ion beam is used to conduct lithography on a diamond (100) surface with the assistance of various gases (Cl2, O2, and XeF2). The beam-induced dilation and sputtering of the surface are measured by atomic force microscope. The dilation is found to be insensitive to the presence of assisting gases at low doses, while the sputtering is enhanced by O2 and XeF2 at high doses. The topographic evolution as a function of the ion dose is well described by a proposed semiempirical equation. Combining physical sputtering and XeF2-assisted etching, the lithographic process has been used to fabricate submicron structures on diamond surfaces.

  11. Focused-ion-beam-assisted fabrication of polymer rolled-up microtubes

    NASA Astrophysics Data System (ADS)

    Luchnikov, V.; Stamm, M.; Akhmadaliev, Ch; Bischoff, L.; Schmidt, B.

    2006-08-01

    A focused ion beam (FIB) has been applied to the fabrication of polymer microtubes via the rolling-up technique from poly(4-vinyl pyridine)/polystyrene bilayer films deposited on the top of a sacrificial aluminum layer covering a silicon wafer. The bending forces in the film arise due to different swelling of the bilayer components in acidic water and lead to rolling of the film. The dimensions and position of the rolled-up tubes can be controlled by FIB milling (sputtering) of geometrically well-adjusted openings in the polymer films. This technique can be applied to the structuring of scrolled films formed from different materials without the use of lithographically patterned photoresists. The geometrical patterning of the tube interior can also be done by FIB irradiation.

  12. ALLIGATOR - An apparatus for ion beam assisted deposition with a broad-beam ion source

    NASA Astrophysics Data System (ADS)

    Wituschek, H.; Barth, M.; Ensinger, W.; Frech, G.; Rück, D. M.; Leible, K. D.; Wolf, G. K.

    1992-04-01

    Ion beam assisted deposition is a versatile technique for preparing thin films and coatings for various applications. Up to now a prototype setup for research purposes has been used in our laboratory. Processing of industrial standard workpieces requires a high current ion source with broad beam and high uniformity for homogeneous bombardment. In this contribution a new apparatus for large area samples will be described. It is named ALLIGATOR (German acronym of facility for ion assisted evaporation on transverse movable or rotary targets). In order to have a wide energy range available two ion sources are used. One delivers a beam energy up to 1.3 keV. The other is suitable for energies from 5 keV up to 40 keV. The ``high-energy'' ion source is a multicusp multiaperture source with 180-mA total current and a beam diameter of 280 mm at the target position.

  13. Biaxial Texture Evolution in MgO Films Fabricated Using Ion Beam-Assisted Deposition

    NASA Astrophysics Data System (ADS)

    Xue, Yan; Zhang, Ya-Hui; Zhao, Rui-Peng; Zhang, Fei; Lu, Yu-Ming; Cai, Chuan-Bing; Xiong, Jie; Tao, Bo-Wan

    2016-07-01

    The growth of multifunctional thin films on flexible substrates is important technologically, because flexible electronics require such a platform. In this study, we examined the evolution of biaxial texture in MgO films prepared using ion beam-assisted deposition (IBAD) on a Hastelloy substrate. Texture and microstructure developments were characterized through in situ reflection high-energy electron diffraction monitoring, x-ray diffraction, and atomic force microscopy, which demonstrated that biaxial texture was developed during the nucleation stage (~2.2 nm). The best biaxial texture was obtained with a thickness of approximately 12 nm. As MgO continued to grow, the influence of surface energy was reduced, and film growth was driven by the attempt to minimize volume free-energy density. Thus the MgO grains were subsequently rotated at the (002) direction toward the ion beam. In addition, an approach was developed for accelerating in-plane texture evolution by pre-depositing an amorphous MgO layer before IBAD.

  14. Deposition of biaxially textured yttria-stabilized zirconia by ion-beam-assisted deposition.

    SciTech Connect

    Chudzik, M. P.

    1998-09-17

    Biaxially textured yttria (8 mol %)-stabilized zirconia (YSZ) thin films were deposited on randomly oriented Hastelloy C and Stainless Steel 304 at room temperature as a buffer layer for subsequent deposition of oriented YBa{sub 2}Cu{sub 3}O{sub x} films. The 0.16-1.3 {micro}m thick YSZ films were deposited by e-beam evaporation at rates of 1.2-3.2 {angstrom}/sec. Biaxially textured films were produced with an Ar/O{sub 2} ion beam directed at the substrate during film growth. X-ray diffraction was used to study in-plane and out-of-plane orientation as a function of ion-bombardment angle, film thickness, ion-to-atom flux ratio, and substrate material. In-plane and out-of-plane average-misorientation angles on these YSZ films that were deposited by ion-beam-assisted deposition were as low as 17 and 5.4{degree}, respectively, on as-received substrates.

  15. Mechanical behaviour of metallic thin films on polymeric substrates and the effect of ion beam assistance on crack propagation

    SciTech Connect

    George, M. , E-Mail: matthieu.george@bnfl.com; Coupeau, C.; Colin, J.; Grilhe, J.

    2005-01-10

    The mechanisms of crack propagation in metallic films on polymeric substrates have been studied through in situ atomic force microscopy observations of thin films under tensile stresses and finite element stress calculations. Two series of films - ones deposited with ion beam assistance, the others without - have been investigated. The observations and stress calculations show that ion beam assistance can change drastically the propagation of cracks in coated materials: by improving the adhesion film/substrate, it slows down the delamination process, but in the same time enhances the cracks growth in the thickness of the material.

  16. Two-dimensional silicon-based detectors for ion beam therapy

    NASA Astrophysics Data System (ADS)

    Martišíková, M.; Granja, C.; Jakůbek, J.; Hartmann, B.; Telsemeyer, J.; Huber, L.; Brons, S.; Pospíšil, S.; Jäkel, O.

    2012-02-01

    Radiation therapy with ion beams is a highly precise kind of cancer treatment. As ion beams traverse material, the highest ionization density occurs at the end of their path. Due to this Bragg-peak, ion beams enable higher dose conformation to the tumor and increased sparing of the surrounding tissue, in comparison to standard radiation therapy using high energy photons. Ions heavier than protons offer in addition increased biological effectiveness and lower scattering. The Heidelberg Ion Beam Therapy Center (HIT) is a state-of-the-art ion beam therapy facility and the first hospital-based facility in Europe. It provides proton and carbon ion treatments. A synchrotron is used for ion acceleration. For dose delivery to the patient, narrow pencil-like beams are scanned over the target volume.

  17. Low-damage surface smoothing of laser crystallized polycrystalline silicon using gas cluster ion beam

    NASA Astrophysics Data System (ADS)

    Tokioka, H.; Yamarin, H.; Fujino, T.; Inoue, M.; Seki, T.; Matsuo, J.

    2007-04-01

    Surface smoothing of laser crystallized polycrystalline silicon (poly-Si) films using gas cluster ion beam (GCIB) technology has been studied. It is found that both SF6-GCIB and O2-GCIB decrease the height of hillocks and reduce the surface roughness of the irradiated films. The mean surface roughness value of poly-Si films was reduced from 10.8 nm to 2.8 nm by SF6-GCIB irradiation at 80°. Ultraviolet reflectance measurement reveals that GCIB irradiation causes damage near-surface of the poly-Si films. Formation of the damage, however, can be suppressed by using GCIB irradiation at high incident angle. Effect of GCIB irradiation in a metal-insulator-semiconductor (MIS) capacitor has also been investigated. The capacitance-voltage curves of MIS capacitor with SF6-GCIB irradiation are distorted. On the contrary, the distortion is reduced by O2-GCIB irradiation at 80, which suggests that electrical-activated damage of the films can be decreased by using O2-GCIB irradiation.

  18. Extremely thin silicon ΔE detectors for ion beam analysis

    NASA Astrophysics Data System (ADS)

    Whitlow, Harry J.; Winzell, Thomas; Thungström, Göran

    1998-03-01

    Recent developments in silicon nanotechnology have made feasible the fabrication of ΔE detectors with thickness of 1μm or less. The CHICSi collaboration has been developing thin ΔE detectors for study of reaction products from intermediate energy heavy ion collisions in an ultra high vacuum storage-ring environment. In this paper, we highlight these developments from an ion beam analysis (IBA) viewpoint. The initial part of the paper outlines the characteristics for these detectors for, nuclear reaction analysis (NRA), elastic recoil detection (ERD) using ΔE-E detector telescopes and accelerator mass spectrometry (AMS). Quasi-empirical estimates of the maximum ΔE detector thickness and separating power for the limit of low energy particles (down to 0.1AMeV) reveal that energy straggling is an important limiting factor. Subsequently different methods are presented for fabricating both self-supported and vertically integrated ΔE detectors including recently developed wafer bonding techniques which open up the possibility of producing ΔE-E detector telescopes where the ΔE element is in the hundreds of nm range. Ultimately consideration is given to special requirements for the readout electronics because of the high capacitance presented by the thin ΔE detectors.

  19. Exchange bias in polycrystalline magnetite films made by ion-beam assisted deposition

    SciTech Connect

    Kaur, Maninder; Qiang, You; Jiang, Weilin; Burks, Edward C.; Liu, Kai; Namavar, Fereydoon; McCloy, John S.

    2014-11-07

    Iron oxide films were produced using ion-beam-assisted deposition, and Raman spectroscopy and x-ray diffraction indicate single-phase magnetite. However, incorporation of significant fractions of argon in the films from ion bombardment is evident from chemical analysis, and Fe/O ratios are lower than expected from pure magnetite, suggesting greater than normal disorder. Low temperature magnetometry and first-order reversal curve measurements show strong exchange bias, which likely arises from defects at grain boundaries, possibly amorphous, creating frustrated spins. Since these samples contain grains ∼6 nm, a large fraction of the material consists of grain boundaries, where spins are highly disordered and reverse independently with external field.

  20. Exchange bias in polycrystalline magnetite films made by ion-beam assisted deposition

    SciTech Connect

    Kaur, Maninder; Jiang, Weilin; Qiang, You; Burks, Edward; Liu, Kai; Namavar, Fereydoon; Mccloy, John S.

    2014-11-03

    Iron oxide films were deposited onto Si substrates using ion-beam-assisted deposition. The films were ~300 nm thick polycrystalline magnetite with an average crystallite size of ~6 nm. Additionally, incorporation of significant fractions of argon in the films from ion bombardment is evident from chemical analysis, and Fe/O ratios are lower than expected from pure magnetite. However, Raman spectroscopy and x-ray diffraction both indicate that the films are single-phase magnetite. Since no direct evidence of a second phase could be found, exchange bias likely arises due to defects at grain boundaries, possibly amorphous, creating frustrated spins. Since these samples have such small grains, a large fraction of the material consists of grain boundaries, where spins are highly disordered and reverse independently with external field. The high energy deposition process results in an oxygen-rich, argon-containing magnetite film with low temperature exchange bias due to defects at the high concentration of grain boundaries.

  1. Planar nanosized field emission cathodes on the basis of graphene/semi-insulating silicon carbide fabricated by focused ion beam

    NASA Astrophysics Data System (ADS)

    Jityaev, L.; Ageev, O. A.; Svetlichnyi, A. M.; Kolomiytsev, A. S.; Spiridonov, O. B.

    2016-08-01

    We investigate the field emission properties of planar graphene structures with nanosized interelectrode distance. The graphene was obtained by thermal decomposition of silicon carbide in vacuum. Planar field emission structures on the basis of graphene on semiinsulating SiC were fabricated by using focused ion beam. We have performed current-voltage measurement on graphene/SiC field emission cathodes. The planar field emission structures showed a threshold voltage less than 1 V.

  2. Surface science studies on the interaction of nitrogen trifluoride ion beams and plasmas with silicon

    NASA Astrophysics Data System (ADS)

    Little, Thomas William

    As microelectronic dimensions continue to shrink, the role of plasma etching assumes greater importance. Recently, there has been considerable interest in using nitrogen trifluoride (NF3) to replace perfluorocarbon (PFC) etchants in some applications. Nitrogen trifluoride is capable of high etching rates, environmentally more tolerable than PFCs, and eliminates buildup of macroscopic carbonaceous surface layers. Literature exists on NF3 etch rate, selectivity and profiles during plasma etching, but very little has been done in the way of detailed surface science examinations of the interaction of NF3 with silicon (Si) surfaces. Scientifically, NF3 offers an ideal tool to probe the surface science of plasma-Si interaction during etching. Previous studies of fluorine (F) etching of Si have relied on either F2, atomic F, or an inert gas compound such as XeF2. The present work employs a gas in which both atoms (N, F) are chemically active, and is one of the first surface science examinations of NF3-Si interaction. Through the complementary use of ion beams and actual plasmas, the effects of ions and neutrals inherent in the plasma have been separated. X-ray photoelectron spectroscopy (XPS) shows that the neutrals are responsible for Si-F bonding while ions are incorporated in complex Si-N-F moieties. The results show for the first time that N is incorporated in Si during the initial stages of etching. Quantum mechanical calculations based on density functional theory (DFT) have been used to augment the XPS results. Finally, severe plasma etching produces anomalous XPS results which can be attributed to differential charging. Mechanistically, the charging is caused by ion bombardment damage during etching as evidenced by atomic force microscopy (AFM). The differential charging behavior has been studied, and it is suggested that the phenomenon may be utilized to quantify plasma etch damage.

  3. Effects of space exposure on ion-beam-deposited silicon-carbide and boron-carbide coatings.

    PubMed

    Keski-Kuha, R A; Blumenstock, G M; Fleetwood, C M; Schmitt, D R

    1998-12-01

    Two recently developed optical coatings, ion-beam-deposited silicon carbide and ion-beam-deposited boron carbide, are very attractive as coatings on optical components for instruments for space astronomy and earth sciences operating in the extreme-UV spectral region because of their high reflectivity, significantly higher than any conventional coating below 105 nm. To take full advantage of these coatings in space applications, it is important to establish their ability to withstand exposure to the residual atomic oxygen and other environmental effects at low-earth-orbit altitudes. The first two flights of the Surface Effects Sample Monitor experiments flown on the ORFEUS-SPAS and the CRISTA-SPAS Shuttle missions provided the opportunity to study the effects of space exposure on these materials. The results indicate a need to protect ion-beam-deposited silicon-carbide-coated optical components from environmental effects in a low-earth orbit. The boron-carbide thin-film coating is a more robust coating able to withstand short-term exposure to atomic oxygen in a low-earth-orbit environment.

  4. Ion beam assisted deposition of MgO barriers for magnetic tunnel junctions

    SciTech Connect

    Cardoso, S.; Macedo, R. J.; Ferreira, R.; Augusto, A.; Wisniowski, P.; Freitas, P. P.

    2008-04-01

    This work reports for the first time results on MgO tunnel junctions prepared by ion beam. The MgO barrier was deposited from a ceramic MgO target using an assisted beam, following the deposition and assisted beam phase diagram which relate the beam profile with the current and energy. The deposition rate for MgO is calculated with and without assisted beam, and compared with the experimental values. The MgO film growth on Ta/CoFeB/MgO simple stacks was optimized aiming at a (002) preferred orientation for the MgO growth, measured by x-ray diffraction. The optimum assist beam energy was tuned for each deposition beam condition (+800,+1000,+1200 V), using assist beams of 40 mA ({approx}130 {mu}A/cm{sup 2}) with 0 to +600 V. Without assist beam, no texture is observed for the MgO, while the (002) orientation appears for assisted deposition. The optimum range of assist voltages is large, being limited by the onset of etching at high voltages, reducing the deposition rate. Magnetic tunnel junctions were deposited with the structure Ta 50 A/Ru 200 A/Ta 50 A/Mn{sub 78}Ir{sub 22} 150 A/Co{sub 90}Fe{sub 10} 30 A/Ru 8 A/Co{sub 56}Fe{sub 24}B{sub 20} 40 A/MgO t/Co{sub 56}Fe{sub 24}B{sub 20} 30 A/Ru 30 A/Ta 50 A, with the MgO barrier deposited with the conditions optimized by x rays. The effect of the assist beam energy on the junction properties (magnetoresistance and magnetization) are discussed. Tunnel magnetoresistance values up to 110%, with RA products of 100-400 {omega} {mu}m{sup 2}, for 11 A thick MgO barriers are obtained using assisted deposition with a +100 V assist beam, which is a major improvement of the {approx}30% of TMR, if no beam is used.

  5. Nonpropulsive applications of ion beams

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    Eight centimeter ion beam sources utilizing xenon and argon have been developed that operate over a wide range of beam energies and currents. Three types of processes have been studied: sputter deposition, ion beam machining, and ion beam surface texturing. The broad range of source operating conditions allows optimum sputter deposition of various materials. An ion beam source was used to ion mill laser reflection holograms using photoresist patterns on silicon. Ion beam texturing was tried with many materials and has a multitude of potential applications.

  6. Through-silicon via plating void metrology using focused ion beam mill

    NASA Astrophysics Data System (ADS)

    Rudack, A. C.; Nadeau, J.; Routh, R.; Young, R. J.

    2012-03-01

    1 μA of ion beam current for fast material removal. At a lower current, the LMIS outperforms the ICP source, but imaging resolution below 30 nm has been demonstrated with ICP-based systems. In addition, the ICP source allows a wide range of possible ion species, with Xe currently the milling species of choice, due to its high mass and favorable ion source performance parameters. Using a 1 μA Xe beam will have an overall milling rate for silicon some 20X higher than a Ga beam operating at 65 nA. This paper will compare the benefits already seen using the Ga-based FIB-SEM approach to TSV metrology, with the improvements in throughput and time-to-data obtained by using the faster material removal capabilities of a FIB based on an ICP ion source. Plasma FIB (PFIB) is demonstrated to be a feasible tool for TSV plating void metrology.

  7. Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer.

    PubMed

    Wang, Andrew; Butte, Manish J

    2014-08-01

    We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, and results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished. PMID:25161320

  8. Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer

    NASA Astrophysics Data System (ADS)

    Wang, Andrew; Butte, Manish J.

    2014-08-01

    We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, and results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished.

  9. Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer

    SciTech Connect

    Wang, Andrew; Butte, Manish J.

    2014-08-04

    We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, and results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished.

  10. Structural and magnetic studies of thin Fe57 films formed by ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Lyadov, N. M.; Bazarov, V. V.; Vagizov, F. G.; Vakhitov, I. R.; Dulov, E. N.; Kashapov, R. N.; Noskov, A. I.; Khaibullin, R. I.; Shustov, V. A.; Faizrakhmanov, I. A.

    2016-08-01

    Thin Fe57 films with the thickness of 120 nm have been prepared on glass substrates by using the ion-beam-assisted deposition technique. X-ray diffraction, electron microdiffraction and Mössbauer spectroscopy studies have shown that as-deposited films are in a stressful nanostructured state containing the nanoscaled inclusions of α-phase iron with the size of ∼10 nm. Room temperature in-plane and out-of-plane magnetization measurements confirmed the presence of the magnetic α-phase in the iron film and indicated the strong effect of residual stresses on magnetic properties of the film as well. Subsequent thermal annealing of iron films in vacuum at the temperature of 450 °C stimulates the growth of α-phase Fe crystallites with the size of up to 20 nm. However, electron microdiffraction and Mössbauer spectroscopic data have shown the partial oxidation and carbonization of the iron film during annealing. The stress disappeared after annealing of the film. The magnetic behaviour of the annealed samples was characterized by the magnetic hysteresis loop with the coercive field of ∼10 mT and the saturation magnetization decreased slightly in comparison with the α-phase Fe magnetization due to small oxidation of the film.

  11. Cluster ion beam assisted fabrication of metallic nanostructures for plasmonic applications

    NASA Astrophysics Data System (ADS)

    Saleem, Iram; Tilakaratne, Buddhi P.; Li, Yang; Bao, Jiming; Wijesundera, Dharshana N.; Chu, Wei-Kan

    2016-08-01

    We report a high-throughput, single-step method for fabricating rippled plasmonic nanostructure arrays via self-assembly induced by oblique angle cluster ion beam irradiation of metal surfaces. This approach does not require lithographic or chemical processes and has the prominent advantage of possible large surface area coverage and applicability to different starting materials. The polarization dependent plasmonic property of the gold nano-ripple is due to their one dimension structure. The localized plasmon resonance frequency of synthesized nano-ripple arrays is tunable by changing nano-ripple dimensions that can be engineered by changing the cluster ion beam irradiation parameters. In this specific case presented, using 30 keV Ar-gas cluster ion beam, we fabricate gold nano-ripple arrays that show localized plasmon resonance in the visible range through near IR range, tunable by varying cluster ion irradiation fluence.

  12. First Observation of the Deflection of a 33 TeV Pb Ion Beam in a Bent Silicon Crystal

    NASA Astrophysics Data System (ADS)

    Elsener, K.; Biino, C.; Clement, M.; Doble, N.; Gatignon, L.; Grafstrom, P.; Mikkelsen, U.; Taratin, A.; Møller, S. P.; Uggerhøj, E.

    1997-05-01

    The deflection of an ultra-relativistic, fully stripped Pb(82+) ion beam in a bent silicon crystal has been observed for the first time. The ions were provided by the CERN-SPS in the H4 beam at a momentum of 400 GeV/c/Z. A 60 mm long silicon crystal, bent over 50 mm to give a 4 mrad deflection angle, was used in this experiment. The measured Pb ion deflection efficiencies are comparable to the ones obtained with protons at an equivalent ratio p/Z, and are found to be about 15% for a beam with a divergence of 50 microradians (FWHM). The interaction rate observed in a background counter is reduced by about the same 15% when the crystal is well aligned with the beam. This corroborates further the channeling model, which predicts that channeled ions are steered away from regions of high electron densities as well as from the nuclei in the crystal.

  13. Full characterization of laser-accelerated ion beams using Faraday cup, silicon carbide, and single-crystal diamond detectors

    SciTech Connect

    Margarone, D.; Prokupek, J.; Rus, B.; Krasa, J.; Velyhan, A.; Laska, L.; Giuffrida, L.; Torrisi, L.; Picciotto, A.; Nowak, T.; Musumeci, P.; Mocek, T.; Ullschmied, J.

    2011-05-15

    Multi-MeV beams of light ions have been produced using the 300 picosecond, kJ-class iodine laser, operating at the Prague Asterix Laser System facility in Prague. Real-time ion diagnostics have been performed by the use of various time-of-flight (TOF) detectors: ion collectors (ICs) with and without absorber thin films, new prototypes of single-crystal diamond and silicon carbide detectors, and an electrostatic ion mass spectrometer (IEA). In order to suppress the long photopeak induced by soft X-rays and to avoid the overlap with the signal from ultrafast particles, the ICs have been shielded with Al foil filters. The application of large-bandgap semiconductor detectors (>3 eV) ensured cutting of the plasma-emitted visible and soft-UV radiation and enhancing the sensitivity to the very fast proton/ion beams. Employing the IEA spectrometer, various ion species and charge states in the expanding laser-plasma have been determined. Processing of the experimental data based on the TOF technique, including estimation of the plasma fast proton maximum and peak energy, ion beam currents and total charge, total number of fast protons, as well as deconvolution processes, ion stopping power, and ion/photon transmission calculations for the different metallic filters used, are reported.

  14. Recrystallization of silicon-on-sapphire structures at various amorphization-ion-beam energies

    SciTech Connect

    Alexandrov, P. A. Demakov, K. D.; Shemardov, S. G.; Kuznetsov, Yu. Yu.

    2013-02-15

    Silicon films on sapphire substrates are grown via recrystallization from the silicon-sapphire interface. An amorphous layer is formed using ion implantation with silicon ion energies of 90-150 keV. An X-ray rocking curve is used to estimate the crystalline perfection of the silicon films. After recrystallization, the silicon layer consists of two parts with different crystalline quality. The recrystallized silicon-on-sapphire structures have a highly perfect upper layer (for fabricating microelectronic devices) and a lower layer adjacent to the sapphire substrate containing a large number of defects.

  15. Single-crystal cubic boron nitride thin films grown by ion-beam-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Hirama, Kazuyuki; Taniyasu, Yoshitaka; Karimoto, Shin-ichi; Krockenberger, Yoshiharu; Yamamoto, Hideki

    2014-03-01

    We investigated the formation of cubic boron nitride (c-BN) thin films on diamond (001) and (111) substrates by ion-beam-assisted molecular beam epitaxy (MBE). The metastable c-BN (sp3-bonded BN) phase can be epitaxially grown as a result of the interplay between competitive phase formation and selective etching. We show that a proper adjustment of acceleration voltage for N2+ and Ar+ ions is a key to selectively discriminate non-sp3 BN phases. At low acceleration voltage values, the sp2-bonded BN is dominantly formed, while at high acceleration voltages, etching dominates irrespective of the bonding characteristics of BN.

  16. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    NASA Astrophysics Data System (ADS)

    Ozcan, Ahmet S.; Lavoie, Christian; Alptekin, Emre; Jordan-Sweet, Jean; Zhu, Frank; Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M.

    2016-04-01

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  17. Ion beam injected point defects in crystalline silicon: Migration, interaction, and trapping phenomena

    SciTech Connect

    Priolo, F.; Libertino, S. |; Privitera, V.; Coffa, S.

    1997-11-01

    The recent work on the room temperature migration and trapping phenomena of ion beam generated point defects in crystalline Si is reviewed. It is shown that a small fraction ({approximately}10{sup {minus}6}) of the defects generated at the surface by a shallow implant is injected into the bulk. These defects undergo a long range trap-limited diffusion and interact with both impurities, dopants and preexisting defects along their path. In particular, these interactions result in dopant deactivation and/or partial annihilation of pre-existing vacancy-type defect markers. It is found that in highly pure, epitaxial Si layers, these effects extend to several microns from the surface, demonstrating a long range migration of point defects at room temperature. By a detailed analysis of the experimental evidences the authors have identified the Si self-interstitials as the major responsible for the observed phenomena. This allowed them to give a lower limit of 6 {times} 10{sup {minus}11} cm{sup 2}/s for the room temperature diffusion coefficient of the Si self-interstitials. Room temperature trap-limited migration of vacancies is also detected as a broadening in the divacancy profile of as implanted samples. In this case the room temperature diffusion coefficient of vacancies has been found to be {ge}3 {times} 10{sup {minus}12} cm{sup 2}/s. These data are presented and their implications discussed.

  18. Ion-beam nanopatterning of silicon surfaces under codeposition of non-silicide-forming impurities

    NASA Astrophysics Data System (ADS)

    Moon, B.; Yoo, S.; Kim, J.-S.; Kang, S. J.; Muñoz-García, J.; Cuerno, R.

    2016-03-01

    We report experiments on surface nanopatterning of Si targets which are irradiated with 2-keV Ar+ ions impinging at near-glancing incidence, under concurrent codeposition of Au impurities simultaneously extracted from a gold target by the same ion beam. Previous recent experiments by a number of groups suggest that silicide formation is a prerequisite for pattern formation in the presence of metallic impurities. In spite of the fact that Au is known not to form stable compounds with the Si atoms, ripples nonetheless emerge in our experiments with nanometric wavelengths and small amplitudes, and with an orientation that changes with distance to the Au source. We provide results of sample analysis through Auger electron and energy-dispersive x-ray spectroscopies for their space-resolved chemical composition, and through atomic force, scanning transmission electron, and high-resolution transmission microscopies for their morphological properties. We discuss these findings in the light of current continuum models for this class of systems. The composition of and the dynamics within the near-surface amorphized layer that ensues is expected to play a relevant role to account for the unexpected formation of these surface structures.

  19. Investigation of electrochemical etch differences in AlGaAs heterostructures using Cl{sub 2} ion beam assisted etching

    SciTech Connect

    Anglin, Kevin Goodhue, William D.; Swint, Reuel B.; Porter, Jeanne

    2015-03-15

    A deeply etched, anisotropic 45° and 90° mirror technology is developed for Al{sub x}Ga{sub 1−x}As heterostructures using a Cl{sub 2} ion beam assisted etching system. When etching vertically, using a conductive low-erosion Ni mask, electrochemical etch differences between layers with various Al mole fractions caused nonuniform sidewall profiles not seen in semi-insulating GaAs test samples. These variations, based on alloy composition, were found to be negligible when etching at a 45°. A Si{sub 3}N{sub 4}-Ni etch mask is designed in order to electrically isolate charge buildup caused by the incoming Ar{sup +} ion beam to the Ni layer, preventing conduction to the underlying epitaxial layers. This modification produced smoothly etched facets, up to 8 μm in depth, enabling fabrication of substrate–surface-emitting slab-coupled optical waveguide lasers and other optoelectronic devices.

  20. Focused ion beam assisted three-dimensional rock imaging at submicron scale

    SciTech Connect

    Tomutsa, Liviu; Radmilovic, Velimir

    2003-05-09

    Computation of effective flow properties of fluids in porous media based on three dimensional (3D) pore structure information has become more successful in the last few years, due to both improvements in the input data and the network models. Computed X-ray microtomography has been successful in 3D pore imaging at micron scale, which is adequate for many sandstones. For other rocks of economic interest, such as chalk and diatomite, submicron resolution is needed in order to resolve the 3D-pore structure. To achieve submicron resolution, a new method of sample serial sectioning and imaging using Focused Ion Beam (FIB) technology has been developed and 3D pore images of the pore system for diatomite and chalk have been obtained. FIB was used in the milling of layers as wide as 50 micrometers and as thin as 100 nanometers by sputtering of atoms from the sample surface. The focused ion beam, consisting of gallium ions (Ga+) accelerated by potentials of up to 30 kV and currents up to 20,000 pA, yields very clean, flat surfaces in which the pore-grain boundaries appear in high contrast. No distortion of the pore boundaries due to the ion milling is apparent. After each milling step, as a new surface is exposed, an image of the surface is generated. Using secondary electrons or ions, resolutions as high as 10 nm can be obtained. Afterwards, the series of 2D images can be stacked in the computer and, using appropriate interpolation and surface rendering algorithms, the 3D pore structure is reconstructed.

  1. Optical properties of ion beam textured metals. [using copper, silicon, aluminum, titanium and stainless steels

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.; Weigand, A. J.; Mirtich, M. J.

    1977-01-01

    Copper, silicon, aluminum, titanium and 316 stainless steel were textured by 1000 eV xenon ions from an 8 cm diameter electron bombardment ion source. Simultaneously sputter-deposited tantalum was used to facilitate the development of the surface microstructure. Scanning electron microscopy of the ion textured surfaces revealed two types of microstructure. Copper, silicon, and aluminum developed a cone structure with an average peak-to-peak distance ranging from 1 micron for silicon to 6 microns for aluminum. Titanium and 316 stainless steel developed a serpentine ridge structure. The average peak-to-peak distance for both of these materials was 0.5 micron. Spectral reflectance was measured using an integrating sphere and a holraum reflectometer. Total reflectance for air mass 0 and 2, solar absorptance and total emittance normalized for a 425 K black body were calculated from the reflectance measurements.

  2. Ion Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Yamada, I.

    The following sections are included: * FILM FORMATION BY ION BEAMS * Fundamental Processes in Film Formation by Low Energy Ion Beams * Comparison of ICB with Other Physical Vapor Deposition Methods * Vacuum Deposition * Sputter Deposition * Ion Plating * Ion Beam Deposition * Simultaneous Deposition and Implantation * Plasma Enhanced Deposition * Section I References * ION CLUSTER BEAM DEPOSITION AND CLUSTER BEAM FORMATION * Nucleation Process * Growth and Condensation Process * Section II References * CHARACTERISTICS OF THE CLUSTER * Velocity of Clusters * Energy of Clusters * TEM Observation of Clusters * Structural Properties * Section III References * IONIZED CLUSTER BEAM DEPOSITION SYSTEM * Section IV References * FILM DEPOSITION PROCESS BY ICB * Fundamental Process * Effects of Kinetic Energy on the Film Properties * Epitaxial phenomena * Crystallographic Structure * Physical Structure of Films * Effects of the Electric Charge on the Film Properties * Section V References * APPLICATIONS * Silicon and Silicon Alloy Films * Low Temperature Epitaxy of Silicon Films * Thermally Stable a-Si Film Growth * High Quality SiO2 Film Deposition * Epitaxial A1 Films * Electromigration Resistant A1 Film * Thermally Stable Al/Si Contact * II-VI and III-V Compound Films * Thin Multiple Layered Film * CONCLUSIONS * Acknowledgements * Section VI References

  3. Ion Beam Analysis Of Silicon-Based Surfaces And Correlation With Surface Energy Measurements

    NASA Astrophysics Data System (ADS)

    Xing, Qian; Herbots, N.; Hart, M.; Bradley, J. D.; Wilkens, B. J.; Sell, D. A.; Sell, Clive H.; Kwong, Henry Mark; Culbertson, R. J.; Whaley, S. D.

    2011-06-01

    The water affinity of Si-based surfaces is quantified by contact angle measurement and surface free energy to explain hydrophobic or hydrophilic behavior of silicone, silicates, and silicon surfaces. Surface defects such as dangling bonds, surface free energy including Lewis acid-base and Lifshitz-van der Waals components are discussed. Water nucleation and condensation is further explained by surface topography. Tapping mode atomic force microscopy (TMAFM) provides statistical analysis of the topography of these Si-based surfaces. The correlation of the above two characteristics describes the behavior of water condensation at Si-based surfaces. Surface root mean square roughness increasing from several Å to several nm is found to provide nucleation sites that expedite water condensation visibly for silica and silicone. Hydrophilic surfaces have a condensation pattern that forms puddles of water while hydrophobic surfaces form water beads. Polymer adsorption on these surfaces alters the water affinity as well as the surface topography, and therefore controls condensation on Si-based surfaces including silicone intraocular lens (IOL). The polymer film is characterized by Rutherford backscattering spectrometry (RBS) in conjunction with 4.265 MeV 12C(α, α)12C, 3.045 MeV 16O(α,α)16O nuclear resonance scattering (NRS), and 2.8 MeV elastic recoil detection (ERD) of hydrogen for high resolution composition and areal density measurements. The areal density of hydroxypropyl methylcellulose (HPMC) film ranges from 1018 atom/cm2 to 1019 atom/cm2 gives the silica or silicone surface a roughness of several Å and a wavelength of 0.16±0.02 μm, and prevents fogging by forming a complete wetting layer during water condensation.

  4. Ion Beam Analysis Of Silicon-Based Surfaces And Correlation With Surface Energy Measurements

    SciTech Connect

    Xing Qian; Herbots, N.; Hart, M.; Bradley, J. D.; Wilkens, B. J.; Sell, D. A.; Culbertson, R. J.; Whaley, S. D.; Sell, Clive H.; Kwong, Henry Mark Jr.

    2011-06-01

    The water affinity of Si-based surfaces is quantified by contact angle measurement and surface free energy to explain hydrophobic or hydrophilic behavior of silicone, silicates, and silicon surfaces. Surface defects such as dangling bonds, surface free energy including Lewis acid-base and Lifshitz-van der Waals components are discussed. Water nucleation and condensation is further explained by surface topography. Tapping mode atomic force microscopy (TMAFM) provides statistical analysis of the topography of these Si-based surfaces. The correlation of the above two characteristics describes the behavior of water condensation at Si-based surfaces. Surface root mean square roughness increasing from several A ring to several nm is found to provide nucleation sites that expedite water condensation visibly for silica and silicone. Hydrophilic surfaces have a condensation pattern that forms puddles of water while hydrophobic surfaces form water beads. Polymer adsorption on these surfaces alters the water affinity as well as the surface topography, and therefore controls condensation on Si-based surfaces including silicone intraocular lens (IOL). The polymer film is characterized by Rutherford backscattering spectrometry (RBS) in conjunction with 4.265 MeV {sup 12}C({alpha}, {alpha}){sup 12}C, 3.045 MeV {sup 16}O({alpha},{alpha}){sup 16}O nuclear resonance scattering (NRS), and 2.8 MeV elastic recoil detection (ERD) of hydrogen for high resolution composition and areal density measurements. The areal density of hydroxypropyl methylcellulose (HPMC) film ranges from 10{sup 18} atom/cm{sup 2} to 10{sup 19} atom/cm{sup 2} gives the silica or silicone surface a roughness of several A ring and a wavelength of 0.16{+-}0.02 {mu}m, and prevents fogging by forming a complete wetting layer during water condensation.

  5. Single-crystal cubic boron nitride thin films grown by ion-beam-assisted molecular beam epitaxy

    SciTech Connect

    Hirama, Kazuyuki Taniyasu, Yoshitaka; Karimoto, Shin-ichi; Krockenberger, Yoshiharu; Yamamoto, Hideki

    2014-03-03

    We investigated the formation of cubic boron nitride (c-BN) thin films on diamond (001) and (111) substrates by ion-beam-assisted molecular beam epitaxy (MBE). The metastable c-BN (sp{sup 3}-bonded BN) phase can be epitaxially grown as a result of the interplay between competitive phase formation and selective etching. We show that a proper adjustment of acceleration voltage for N{sub 2}{sup +} and Ar{sup +} ions is a key to selectively discriminate non-sp{sup 3} BN phases. At low acceleration voltage values, the sp{sup 2}-bonded BN is dominantly formed, while at high acceleration voltages, etching dominates irrespective of the bonding characteristics of BN.

  6. Tailoring the Optical Properties of Silicon with Ion Beam Created Nanostructures for Advanced Photonics Applications

    NASA Astrophysics Data System (ADS)

    Akhter, Perveen

    In today's fast life, energy consumption has increased more than ever and with that the demand for a renewable and cleaner energy source as a substitute for the fossil fuels has also increased. Solar radiations are the ultimate source of energy but harvesting this energy in a cost effective way is a challenging task. Si is the dominating material for microelectronics and photovoltaics. But owing to its indirect band gap, Si is an inefficient light absorber, thus requiring a thickness of solar cells beyond tens of microns which increases the cost of solar energy. Therefore, techniques to increase light absorption in thin film Si solar cells are of great importance and have been the focus of research for a few decades now. Another big issue of technology in this fast-paced world is the computing rate or data transfer rate between components of a chip in ultra-fast processors. Existing electronic interconnects suffering from the signal delays and heat generation issues are unable to handle high data rates. A possible solution to this problem is in replacing the electronic interconnects with optical interconnects which have large data carrying capacity. However, optical components are limited in size by the fundamental laws of diffraction to about half a wavelength of light and cannot be combined with nanoscale electronic components. Tremendous research efforts have been directed in search of an advanced technology which can bridge the size gap between electronic and photonic worlds. An emerging technology of "plasmonics'' which exploits the extraordinary optical properties of metal nanostructures to tailor the light at nanoscale has been considered a potential solution to both of the above-mentioned problems. Research conducted for this dissertation has an overall goal to investigate the optical properties of silicon with metal nanostructures for photovoltaics and advanced silicon photonics applications. The first part of the research focuses on achieving enhanced

  7. Fabrication of single TiO2 nanotube devices with Pt interconnections using electron- and ion-beam-assisted deposition

    NASA Astrophysics Data System (ADS)

    Lee, Mingun; Cha, Dongkyu; Huang, Jie; Ha, Min-Woo; Kim, Jiyoung

    2016-06-01

    Device fabrication using nanostructured materials, such as nanotubes, requires appropriate metal interconnections between nanotubes and electrical probing pads. Here, electron-beam-assisted deposition (EBAD) and ion-beam-assisted deposition (IBAD) techniques for fabrication of Pt interconnections for single TiO2 nanotube devices are investigated. IBAD conditions were optimized to reduce the leakage current as a result of Pt spreading. The resistivity of the IBAD-Pt was about three orders of magnitude less than that of the EBAD-Pt, due to low carbon concentration and Ga doping, as indicated by X-ray photoelectron spectroscopy analysis. The total resistances of single TiO2 nanotube devices with EBAD- or IBAD-Pt interconnections were 3.82 × 1010 and 4.76 × 108 Ω, respectively. When the resistivity of a single nanotube is low, the high series resistance of EBAD-Pt cannot be ignored. IBAD is a suitable method for nanotechnology applications, such as photocatalysis and biosensors.

  8. Fabrication of micro/nano-structures using focused ion beam implantation and XeF2 gas-assisted etching

    NASA Astrophysics Data System (ADS)

    Xu, Z. W.; Fang, F. Z.; Fu, Y. Q.; Zhang, S. J.; Han, T.; Li, J. M.

    2009-05-01

    A micro/nano-structure fabrication method is developed using focused ion beam implantation (FIBI) and FIB XeF2 gas-assisted etching (FIB-GAE). Firstly, the FIB parameters' influence on the FIBI depth is studied by SEM observation of the FIBI cross-section cutting by FIB. Nanoparticles with 10-15 nm diameter are found to be evenly distributed in the FIBI layer, which can serve as a XeF2-assisted etching mask when the ion dose is larger than 1.4 × 1017 ions cm-2. The FIBI layers being used as the etching mask for the subsequent FIB-GAE process are explored to create different micro/nano-structures such as nano-gratings, nano-electrode and sinusoidal microstructures. It is found that the method of combining FIBI with subsequent FIB-GAE is efficient and flexible in micro/nano-structuring, and it can effectively remove the redeposition effect compared with the FIB milling method.

  9. Hierarchical titania nanostructures prepared with focused ion beam-assisted anodisation of titanium in an aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Yadav, Pradeep K.; Lemoine, Patrick; Dale, Graham; Hamilton, Jeremy W. J.; Dunlop, Patrick S. M.; Byrne, John A.; Mailley, Pascal; Boxall, Colin

    2015-04-01

    Titania nanostructures have been prepared by anodisation in aqueous solution assisted by focused ion beam (FIB) milling. The structures formed are bi-periodic, a disordered "native" nanotube array, with characteristics similar to those formed by the standard anodisation process and an ordered array of tubes with larger diameters, guided by the positioning of the FIB concave pits. Low kV EDX analysis shows implanted Ga in FIB-treated titanium which is efficiently removed by the anodisation process. Following thermal annealing, the FIB-treated regions also crystallise to the same anatase phase as the native regions. This result is in stark contrast to previous FIB-assisted anodisation studies which only produced nanostructured arrays of native dimensions. This singularity is discussed in terms of the stable FIB-induced crystalline defects which, in an aqueous electrolyte, can result in the growth of a weaker barrier layer and larger tubes. This novel process gave hexagonal and square arrays with tailored cross-sectional dimensions and therefore has potential for the synthesis of novel meta-materials.

  10. Visualisation of the ingress of water and dispersion of drugs in a modified hydrosilanised silicone polymer using combined ion beam analysis techniques

    NASA Astrophysics Data System (ADS)

    Jenneson, P. M.; Clough, A. S.; Riggs, P. D.; Sample, I. R.

    1998-08-01

    A combination of the ion beam analysis techniques Nuclear Reaction Analysis (NRA) and Particle Induced X-ray Emission (PIXE) were used to image the ingress of heavy water into a modified hydrosilanised silicone polymer doped with the drug chlorhexidine diacetate. In the drug release system studied chlorine was a unique component of the drug, the polymeric matrix was identified by its silicon component and the diffusing water labelled with deuterium. Areal distribution plots are shown for differing exposure times of the polymer to D 2O. The plots are also statistically analysed to show trends of increasing chlorine/deuterium correlation, silicon/deuterium anti-correlation and a constant silicon/chlorine anti-correlation with respect to time.

  11. Ion-beam sputtering increases solar-cell efficiency

    NASA Technical Reports Server (NTRS)

    Burk, D. E.; Dubow, J. B.; Sites, R. R.

    1977-01-01

    Ion-beam sputtering, fabrication of oxide-semiconductor-on-silicon (OSOS) solar cells, results in cells of 12% efficiency. Ion-beam sputtering technique is compatible with low-cost continuous fabrication and requires no high-temperature processing.

  12. Near infrared rugate filter fabrication by ion beam assisted deposition of Si/sub (1--//sub x//sub )/N/sub x/ films

    SciTech Connect

    Donovan, E. P.; Vechten, D. V.; Carosella, A. D. F.; Hubler, G. K.

    1989-07-15

    The rugate filter employs a sinusoidal refractive index depth profile to produce high reflection in a narrow band of wavelengths. Fabrication relies on a continuously variable index of refraction in the wavelength regime of interest. The near IR refractive index of amorphous silicon--nitrogen films decreases continuously as the composition varies from pure silicon to stoichiometric silicon nitride (Si/sub 3/N/sub 4/). Ion implantation was found unsuitable as a fabrication method for rugate filters. Homogeneous and inhomogeneous films up to 5 /mu/m in thickness have been produced by simultaneous deposition of electron beam evaporated silicon and of energetic nitrogen particles arising from an ion beam. The relative fluxes of beam and evaporant are found to determine the ratio of nitrogen to silicon in the films and therefore to determine the index. Single-band reflection filters of the rugate design of high peak optical density were fabricated under computer control using a quartz crystal oscillator shielded from the beam to monitor the silicon evaporation and three suppressed Faraday cups to monitor the ion beam current.

  13. Much simplified ion-beam assisted deposition-TiN template for high-performance coated conductors

    NASA Astrophysics Data System (ADS)

    Xiong, J.; Matias, V.; Wang, H.; Zhai, J. Y.; Maiorov, B.; Trugman, D.; Tao, B. W.; Li, Y. R.; Jia, Q. X.

    2010-10-01

    A much simplified template, i.e., two nonsuperconducting layers between the superconducting YBa2Cu3O7-δ (YBCO) and the polycrystalline metal substrate, has been developed for high-performance coated conductors by using biaxially aligned TiN as a seed layer. A combination of a thin TiN (˜10 nm by ion-beam assisted deposition) layer and an epitaxial buffer LaMnO3 layer (˜120 nm) allows us to grow epitaxial YBCO films with values of full width at half-maximum around 3.5° and 1.7° for the ϕ-scan of (103) and rocking curve of (005) YBCO, respectively. The YBCO films grown on electropolished polycrystalline Hastelloy using this two-layer template exhibited a superconducting transition temperature of 89.5 K, a critical current density of 1.2 MA/cm2 at 75.5 K, and an α value (proportional factor of critical current density Jc˜H-α) of around 0.33, indicating a high density of pinning centers and an absence of weak links.

  14. High-temperature tribological characteristics of silver and gold coatings on ceramics prepared by ion-beam-assisted deposition

    SciTech Connect

    Erdemir, A.; Erck, R.A.; Fenske, G.R.; Nichols, F.A.

    1992-04-01

    An ion-beam-assisted deposition (IBAD) system was used to deposit silver and gold coatings on polycrystalline {alpha}-alumina (Al{sub 2}O{sub 3}) substrates for tribological studies at temperatures to 400{degrees}C. The wear tests were performed with an oscillating ball-on-flat type of test apparatus as a partial simulation of ring/liner motion and contact geometry in actual engine systems. The test results showed that without a surface coating, both the wear rates and the friction coefficients of Al{sub 2}O{sub 3}/Al{sub 2}O{sub 3} test pairs were quite high, and increased substantially with temperature. In contract, the wear of flats coated with silver and gold was at unmeasurable levels, even after sliding tests of 110,000 passes. The wear of balls (uncoated) sliding against the Ag- and Au-coated flats was reduced by factors of 45 to more than 500 depending on coating type and ambient temperature. The friction coefficients of pairs with an IBAD-Ag or Au coating were in the range of 0.32--0.5.

  15. Chemically assisted ion beam etching of laser diode facets on nonpolar and semipolar orientations of GaN

    NASA Astrophysics Data System (ADS)

    Kuritzky, L. Y.; Becerra, D. L.; Saud Abbas, A.; Nedy, J.; Nakamura, S.; DenBaars, S. P.; Cohen, D. A.

    2016-07-01

    We demonstrate a vertical (<1° departure) and smooth (2.0 nm root mean square line-edge roughness (LER)) etch by chemically assisted Ar ion beam etching (CAIBE) in Cl2 chemistry that is suitable for forming laser diode (LD) facets on nonpolar and semipolar oriented III-nitride devices. The etch profiles were achieved with photoresist masks and optimized CAIBE chamber conditions including the platen tilt angle and Cl2 flow rate. Co-loaded studies showed similar etch rates of ˜60 nm min-1 for (20\\bar{2}\\bar{1}),(20\\bar{2}1), and m-plane orientations. The etched surfaces of LD facets on these orientations are chemically dissimilar (Ga-rich versus N-rich), but were visually indistinguishable, thus confirming the negligible orientation dependence of the etch. Continuous-wave blue LDs were fabricated on the semipolar (20\\bar{2}\\bar{1}) plane to compare CAIBE and reactive ion etch (RIE) facet processes. The CAIBE process resulted in LDs with lower threshold current densities due to reduced parasitic mirror loss compared with the RIE process. The LER, degree of verticality, and model of the 1D vertical laser mode were used to calculate a maximum uncoated facet reflection of 17% (94% of the nominal) for the CAIBE facet. The results demonstrate the suitability of CAIBE for forming high quality facets for high performance nonpolar and semipolar III-N LDs.

  16. Chemically assisted ion beam etching of laser diode facets on nonpolar and semipolar orientations of GaN

    NASA Astrophysics Data System (ADS)

    Kuritzky, L. Y.; Becerra, D. L.; Saud Abbas, A.; Nedy, J.; Nakamura, S.; DenBaars, S. P.; Cohen, D. A.

    2016-07-01

    We demonstrate a vertical (<1° departure) and smooth (2.0 nm root mean square line-edge roughness (LER)) etch by chemically assisted Ar ion beam etching (CAIBE) in Cl2 chemistry that is suitable for forming laser diode (LD) facets on nonpolar and semipolar oriented III-nitride devices. The etch profiles were achieved with photoresist masks and optimized CAIBE chamber conditions including the platen tilt angle and Cl2 flow rate. Co-loaded studies showed similar etch rates of ∼60 nm min‑1 for (20\\bar{2}\\bar{1}),(20\\bar{2}1), and m-plane orientations. The etched surfaces of LD facets on these orientations are chemically dissimilar (Ga-rich versus N-rich), but were visually indistinguishable, thus confirming the negligible orientation dependence of the etch. Continuous-wave blue LDs were fabricated on the semipolar (20\\bar{2}\\bar{1}) plane to compare CAIBE and reactive ion etch (RIE) facet processes. The CAIBE process resulted in LDs with lower threshold current densities due to reduced parasitic mirror loss compared with the RIE process. The LER, degree of verticality, and model of the 1D vertical laser mode were used to calculate a maximum uncoated facet reflection of 17% (94% of the nominal) for the CAIBE facet. The results demonstrate the suitability of CAIBE for forming high quality facets for high performance nonpolar and semipolar III-N LDs.

  17. Durability of Solar Reflective Materials with an Alumina Hard Coat Produced by Ion-Beam-Assisted Deposition: Preprint

    SciTech Connect

    Kennedy, C. E.; Smilgys, R. V.

    2002-10-01

    A promising low-cost reflector material for solar concentrating power (CSP) generation is a silvered substrate protected by an alumina coating several microns thick. The alumina hard coat is deposited under high vacuum by ion-beam-assisted-deposition (IBAD). Samples of this material have been produced both by batch and continuous roll-coating processes. The substrate materials investigated were polyethylene terephthalate (PET), PET laminated to stainless-steel foil, and chrome-plated carbon steel strip. The advantage of steel strip compared to PET is that it withstands a higher process temperature and lowers the final product installation costs. In this paper, we compare the durability of batch and roll-coated reflective materials with an alumina deposition rate as high as 10 nm/s. In general, the durability of the samples is found to be excellent. Comparisons between accelerated and outdoor exposure testing results indicate that these front-surface mirrors are more susceptible to weather conditions not simulated by accelerated tests (i.e., rain, sleet, snow, etc.) than other types of solar reflectors. For long-term durability, edge protection will be necessary, and durability could be improved by the addition of an adhesion-promoting layer between the silver and alumina.

  18. Neutralization of space charge on high-current low-energy ion beam by low-energy electrons supplied from silicon based field emitter arrays

    SciTech Connect

    Gotoh, Yasuhito; Tsuji, Hiroshi; Taguchi, Shuhei; Ikeda, Keita; Kitagawa, Takayuki; Ishikawa, Junzo; Sakai, Shigeki

    2012-11-06

    Neutralization of space charge on a high-current and low-energy ion beam was attempted to reduce the divergence with an aid of low-energy electrons supplied from silicon based field emitter arrays (Si-FEAs). An argon ion beam with the energy of 500 eV and the current of 0.25 mA was produced by a microwave ion source. The initial beam divergence and the emittance were measured at the entrance of the analysis chamber in order to estimate the intrinsic factors for beam divergence. The current density distribution of the beam after transport of 730 mm was measured by a movable Faraday cup, with and without electron supply from Si-FEAs. A similar experiment was performed with tungsten filaments as an electron source. The results indicated that the electron supply from FEA had almost the same effect as the thermionic filament, and it was confirmed that both electron sources can neutralize the ion beam.

  19. Fast prototyping of high-aspect ratio, high-resolution x-ray masks by gas-assisted focused ion beam

    NASA Technical Reports Server (NTRS)

    Hartley, F.; Malek, C.; Neogi, J.

    2001-01-01

    The capacity of chemically-assisted focused ion beam (fib) etching systems to undertake direct and highly anisotropic erosion of thin and thick gold (or other high atomic number [Z])coatings on x-ray mask membranes/substrates provides new levels of precision, flexibility, simplification and rapidity in the manufacture of mask absorber patterns, allowing the fast prototyping of high aspect ratio, high-resolution masks for deep x-ray lithography.

  20. Focused ion beam and electron microscopy characterization of nanosharp tips and microbumps on silicon and metal thin films formed via localized single-pulse laser irradiation

    SciTech Connect

    Moening, Joseph P.; Georgiev, Daniel G.; Lawrence, Joseph G.

    2011-01-01

    Cross-sections of laser fabricated nanosharp tips and microbumps on silicon and metal thin films are produced and examined in this work. These structures are formed with a Q-switched neodymium doped yttrium aluminum garnet nanosecond-pulse laser, emitting at its fourth harmonic of 266 nm, using a mask projection technique to generate circular laser spots, several microns in diameter. Cross-section of selected structures were produced using a focused ion beam and were characterized via electron microscopy. The diffraction patterns of the silicon samples indicate that the laser formed tip maintains the same single crystal structure as the original silicon film. Examinations of the laser formed structures in metal films confirm that the microbumps are hollow, while revealing that the vertical protrusions are solid.

  1. Real time x-ray studies during nanostructure formation on silicon via low energy ion beam irradiation using ultrathin iron films

    SciTech Connect

    El-Atwani, Osman; Suslova, Anastassiya; Gonderman, Sean; Fowler, Justin; El-Atwani, Mohamad; DeMasi, Alexander; Ludwig, Karl; Paul Allain, Jean

    2012-12-24

    Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 Multiplication-Sign 10{sup 15} iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after the removal of all the iron atoms from the sample as confirmed by XRF and ex-situ x-ray photoelectron spectroscopy (XPS). In addition, in-situ XPS results indicated silicide formation, which plays a role in the structure formation mechanism.

  2. Oxygen ion-beam microlithography

    DOEpatents

    Tsuo, Y.S.

    1991-08-20

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used. 5 figures.

  3. Oxygen ion-beam microlithography

    DOEpatents

    Tsuo, Y. Simon

    1991-01-01

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

  4. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications.

    PubMed

    Alias, Mohd S; Yang, Yang; Ng, Tien K; Dursun, Ibrahim; Shi, Dong; Saidaminov, Makhsud I; Priante, Davide; Bakr, Osman M; Ooi, Boon S

    2016-01-01

    The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption. PMID:26688008

  5. Enhanced Etching, Surface Damage Recovery, and Submicron Patterning of Hybrid Perovskites using a Chemically Gas-Assisted Focused-Ion Beam for Subwavelength Grating Photonic Applications.

    PubMed

    Alias, Mohd S; Yang, Yang; Ng, Tien K; Dursun, Ibrahim; Shi, Dong; Saidaminov, Makhsud I; Priante, Davide; Bakr, Osman M; Ooi, Boon S

    2016-01-01

    The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted attention for photonic device applications. However, owing to the sensitivity of organic moieties to solvents and temperature, device processing is challenging, particularly for patterning. Here, we report the direct patterning of perovskites using chemically gas-assisted focused-ion beam (GAFIB) etching with XeF2 and I2 precursors. We demonstrate etching enhancement in addition to controllability and marginal surface damage compared to focused-ion beam (FIB) etching without precursors. Utilizing the GAFIB etching, we fabricated a uniform and periodic submicron perovskite subwavelength grating (SWG) absorber with broadband absorption and nanoscale precision. Our results demonstrate the use of FIB as a submicron patterning tool and a means of providing surface treatment (after FIB patterning to minimize optical loss) for perovskite photonic nanostructures. The SWG absorber can be patterned on perovskite solar cells to enhance the device efficiency through increasing light trapping and absorption.

  6. Ion-beam-assisted deposition of MoS2 and other low-friction films. Interim report, Jun 88-Jun 92

    SciTech Connect

    Bolster, R.N.

    1992-09-11

    Vacuum-deposited films of molybdenum disulfide (MoS2) are effective as solid lubricants. Ion-beam-assisted deposition, which employs ion beam sputtering with an assist beam impinging on the growing film, has been investigated as a means of preparing low-friction high endurance coatings. The apparatus used and some of the techniques involved are described. Ion source operating parameters were optimized and the assist beam ion flux was quantified and found to follow a power-law relationship with beam power. The best way to produce MoS2 films was found to be cosputtering from separate Mo and S targets with deposition rates adjusted to obtain the desired stoichiometry. Deposition rates were found to also follow a power-law relationship with beam power, and formulae are given for predicting them, the ratio of assist ions to film atoms, and the effect of assist beam sputtering on film thickness. Inverse formulae are given for determining process parameters needed to achieve a selected film thickness and composition. A composite target for simultaneous Mo and S sputtering was developed. Deposition rates were determined for other metals: W, N1, Co, Cu, and Pb. Formulae relating target-to-substrate distance to deposition rate are given.

  7. Acetone cluster ion beam irradiation on solid surfaces

    NASA Astrophysics Data System (ADS)

    Ryuto, H.; Kakumoto, Y.; Itozaki, S.; Takeuchi, M.; Takaoka, G. H.

    2013-11-01

    Acetone cluster ions were produced by the adiabatic expansion method without using a support gas. The acceleration voltage of the acetone cluster ion beam was from 3 to 9 kV. The sputter depths of silicon irradiated with acetone cluster ion beams increased with acceleration voltage and fluence of the acetone cluster ion beams. The sputter depth was close to that induced by the ethanol cluster ion beam accelerated at the same acceleration voltage. The sputtering yield of silicon by the acetone cluster ion beam at an acceleration voltage of 9 kV was approximately 100 times larger than that for an argon monomer ion beam at 9 keV. The sputter depths of silicon dioxide irradiated with the acetone cluster ion beams were smaller than those of silicon, but larger than those induced by ethanol cluster ion beams. The XPS analysis of silicon surface indicated that the silicon surface was more strongly oxidized by the irradiation of acetone cluster ion beam than ethanol cluster ion beam.

  8. Detailed subsurface damage measurement and efficient damage-free fabrication of fused silica optics assisted by ion beam sputtering.

    PubMed

    Liao, Wenlin; Dai, Yifan; Liu, Zongzheng; Xie, Xuhui; Nie, Xuqing; Xu, Mingjin

    2016-02-22

    Formation of subsurface damage has an inseparable relationship with microscopic material behaviors. In this work, our research results indicate that the formation process of subsurface damage often accompanies with the local densification effect of fused silica material, which seriously influences microscopic material properties. Interestingly, we find ion beam sputtering (IBS) is very sensitive to the local densification, and this microscopic phenomenon makes IBS as a promising technique for the detection of nanoscale subsurface damages. Additionally, to control the densification effect and subsurface damage during the fabrication of high-performance optical components, a combined polishing technology integrating chemical-mechanical polishing (CMP) and ion beam figuring (IBF) is proposed. With this combined technology, fused silica without subsurface damage is obtained through the final experimental investigation, which demonstrates the feasibility of our proposed method.

  9. Investigation of the mechanism of impurity assisted nanoripple formation on Si induced by low energy ion beam erosion

    SciTech Connect

    Koyiloth Vayalil, Sarathlal; Gupta, Ajay; Roth, Stephan V.; Ganesan, V.

    2015-01-14

    A detailed mechanism of the nanoripple pattern formation on Si substrates generated by the simultaneous incorporation of pure Fe impurities at low energy (1 keV) ion beam erosion has been studied. To understand and clarify the mechanism of the pattern formation, a comparative analysis of the samples prepared for various ion fluence values using two complimentary methods for nanostructure analysis, atomic force microscopy, and grazing incidence small angle x-ray scattering has been done. We observed that phase separation of the metal silicide formed during the erosion does not precede the ripple formation. It rather concurrently develops along with the ripple structure. Our work is able to differentiate among various models existing in the literature and provides an insight into the mechanism of pattern formation under ion beam erosion with impurity incorporation.

  10. Composition and Bonding in Amorphous Carbon Films Grown by Ion Beam Assisted Deposition: Influence of the Assistance Voltage

    SciTech Connect

    Albella, J.M.; Banks, J.C.; Climent-Font, A.; Doyle, B.L.; Gago, R.; Jimenez, I.; Terminello, L.J.

    1998-11-12

    Amorphous carbon films have been grown by evaporation of graphite with concurrent Ar+ ions bombardment assistance. The ion energy has been varied between 0-800 V while keeping a constant ion to carbon atom arrival ratio. Film composition and density were determined by ion scattering techniques (RBS and ERDA), indicating a negligible hydrogen content and a density dependence with the assistance voltage. The bonding structure of the films has been studied by Raman and X-ray Absorption Near-Edge (XANES) spectroscopy. Different qualitative effects have been found depending on the ion energy range. For ion energies below 300 eV, there is a densification of the carbon layer due to the increase in the sp3 content. For ion energies above 300 eV sputtering phenomena dominate over densification, and thinner films are found with increasing assistance voltage until no film is grown over 600 V. The films with the highest SP3 content are grown with intermediate energies between 200-300 V.

  11. In-plane aligned YBCO film on textured YSZ buffer layer deposited on NiCr alloy tape by laser ablation with only O+ ion beam assistance

    NASA Astrophysics Data System (ADS)

    Tang Huang, Xin; Qing Wang, You; Wang, Qiu Liang; Chen, Qing Ming

    2000-02-01

    High critical current density and in-plane aligned YBa2 Cu3 O7-x (YBCO) film on a textured yttria-stabilized zirconia (YSZ) buffer layer deposited on NiCr alloy (Hastelloy c-275) tape by laser ablation with only O+ ion beam assistance was fabricated. The values of the x-ray phi-scan full width at half-maximum (FWHM) for YSZ(202) and YBCO(103) are 18° and 11°, respectively. The critical current density of YBCO film is 7.9 × 105 A cm-2 at liquid nitrogen temperature and zero field, and its critical temperature is 90 K.

  12. Influence of 700 °C vacuum annealing on fracture behavior of micro/nanoscale focused ion beam fabricated silicon structures

    NASA Astrophysics Data System (ADS)

    Goshima, Yoshiharu; Fujii, Tatsuya; Inoue, Shozo; Namazu, Takahiro

    2016-06-01

    In this paper, we describe the influence of 700 °C vacuum annealing on strength and fracture behavior of micro- and nano-scale Si structures fabricated by focused ion beam (FIB). Si nanowires (NWs) made from silicon-on-nothing (SON) membrane are fabricated using FIB. Microscale Si specimens are fabricated by conventional micromachining technologies and FIB. These specimens are tensioned to failure using specially developed microelectromechanical systems (MEMS) device and thin-film tensile tester, respectively. The mean fracture strengths of the nano- and microscale specimens are 5.6 and 1.6 GPa, respectively, which decrease to 2.9 and 0.9 GPa after vacuum annealing at 700 °C for only 10 s. These strength values do not vary with increasing annealing time. Fracture origin and its behavior are discussed in the light of fracture surface and FIB damage layer observations.

  13. Fundamental reliability of 1.5-nm-thick silicon oxide gate films grown at 150 deg. C by modified reactive ion beam deposition

    SciTech Connect

    Yamada, Hiroshi

    2008-01-15

    The reliability of 1.5-nm-thick silicon oxide gate films grown at 150 deg. C by modified reactive ion beam deposition (RIBD) with in situ pyrolytic-gas passivation (PGP) using N{sub 2}O and NF{sub 3} was investigated. RIBD uses low-energy-controlled reactive, ionized species and potentializes low-temperature film growth. Although the oxide films were grown at a low temperature of 150 deg. C, their fundamental indices of reliability, such as the time-dependent dielectric breakdown lifetime and interface state density, were almost equivalent to those of oxide films grown at 850 deg. C using a furnace. This is probably due to localized interfacial N and F atoms. The number density of interfacial N atoms was about seven times larger than that for the furnace-grown oxide films, and this is a key factor for improving the reliability through the compensation of residual inconsistent-state bonding sites.

  14. 1.5-nm-thick silicon oxide gate films grown at 150 deg. C using modified reactive ion beam deposition with pyrolytic-gas passivation

    SciTech Connect

    Yamada, Hiroshi

    2007-03-15

    Low-temperature ultrathin silicon oxide gate film growth using modified reactive ion beam deposition (RIBD) with an in situ pyrolytic-gas passivation (PGP) method is described. RIBD uses low-energy-controlled reactive and ionized species and potentializes low-temperature film growth. By combining RIBD with PGP using N{sub 2}O and NF{sub 3}, 1.5-nm-thick silicon oxide gate films with high-potential barrier height energy, 3.51 eV, and low-leakage current, less than about 10{sup -5} A/cm{sup 2} at 2 MV/cm, can be obtained at a growth temperature of 150 deg. C. From an evaluation of number densities of N, F, and O atoms near the 1.5-5.0-nm-thick RIBD-with-PGP silicon oxide films/Si(100) interfaces, it is believed that interfacial N and F atoms contribute to improve the electrical characteristics and F effectively compensates the residual inconsistent-state bonding sites after the N passivation.

  15. Surface roughness of MgO thin film and its critical thickness for optimal biaxial texturing by ion-beam-assisted deposition

    SciTech Connect

    Miyata, S.; Ibi, A.; Izumi, T.; Shiohara, Y.

    2011-06-01

    We investigated the deposition time dependences of the in-plane grain alignment ({Delta}{phi}) and the surface roughness (w) of biaxially textured MgO thin films fabricated by ion-beam-assisted deposition (IBAD) and found a strong correlation between them. The time evolution of the surface roughness of IBAD-MgO showed an abrupt increase at the same time corresponding to the beginning of the deterioration in {Delta}{phi}. The roughness versus thickness profiles obtained under different deposition conditions with different assisting ion-beam currents collapsed to a single curve, even though the deposition rates were significantly different in each condition. This implies that the abrupt increase in roughness occurred at the same thickness--of about 4 nm--irrespective of the deposition rate. The result also indicated that the {Delta}{phi} deterioration began with the same thickness of about 4 nm. This ''critical'' thickness of about 4 nm might be related to the completion of the crystallization of the film. Further, deposition beyond the critical thickness, therefore, became merely a homoepitaxial deposition under the ''IBAD'' condition, which was far from optimal because of the ion bombardment and low temperature (no-heating), and thus {Delta}{phi} deteriorated. Based on these considerations, we propose an approach to attain a sharp texture in a IBAD-MgO-based biaxial substrate; moreover, we demonstrated this approach using a two-step deposition process.

  16. Nonpropulsive applications of ion beams. [electric propulsion technology utilization

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    This paper describes the results of an investigation of the nonpropulsive applications of electric propulsion technology. Eight centimeter ion beam sources utilizing xenon and argon have been developed that operate over a wide range of beam energies and currents. Three types of processes have been studied - sputter deposition, ion beam machining, and ion beam surface texturing. The broad range of source operating conditions allows optimum sputter deposition of various materials. An ion beam source has also been used to ion mill laser reflection holograms using photoresist patterns on silicon. Ion beam texturing has been tried with many materials and has a multitude of potential applications.

  17. Tunneling behavior in ion-assist ion-beam sputtered CoFe/MgO/NiFe magnetic tunnel junctions

    SciTech Connect

    Singh, Braj Bhusan; Chaudhary, Sujeet; Pandya, Dinesh K.

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ► Dual ion beam sputtered MgO barrier for MTJs. ► ∼12% TMR at 60 K. ► Glazman and Matveev model fitted for quantification of elastic and inelastic tunneling conductance through barrier. -- Abstract: Magnetic tunnel junctions (MTJs) consisting of CoFe and NiFe as ferromagnetic electrodes and MgO as insulating barrier fabricated through in situ shadow masking employing ion beam sputtering are studied for their tunneling magnetoresistance (TMR) and temperature dependence of the tunneling conductance behavior. The tunneling characteristics of these MTJs exhibited barrier height of 0.7 eV and width of 3.3 nm. These MTJs possessed ∼12% TMR at 60 K. The temperature dependence of conductance behavior of these junctions have revealed finite contributions from inelastic tunneling through the barrier via hopping conduction via present localized states which arise due to the presence of ionic interstitial defects in the MgO oxide barrier. The fitting of the data reveals that thirteenth order of hopping conduction is operative through MgO barrier.

  18. Influence of Ag thickness on structural, optical, and electrical properties of ZnS/Ag/ZnS multilayers prepared by ion beam assisted deposition

    SciTech Connect

    Leng Jian; Yu Zhinong; Xue Wei; Zhang Ting; Jiang Yurong; Zhang Jie; Zhang Dongpu

    2010-10-15

    The structural, optical, and electrical characteristics of zinc sulfide (ZnS)/Ag/ZnS (ZAZ) multilayer films prepared by ion beam assisted deposition on k9 glass have been investigated as a function of Ag layer thickness. The characteristics of ZAZ multilayer are significantly improved up insertion of optimal Ag thickness between ZnS layers. The results show that due to bombardment of Ar ion beam, distinct Ag islands evolve into continuous Ag films at a thin Ag thickness of about 4 nm. The thinner Ag film as a thickness of 2 nm leads to high sheet resistance and low transmittance for the interface scattering induced by the Ag islands or noncontinuous films; and when the Ag thickness is over 4 nm, the ZAZ multilayer exhibits a remarkably reduced sheet resistance between 7-80 {Omega}/sq for the increase in carrier concentration and mobility of Ag layer, and a high transmittance over 90% for the interference phenomena of multilayers and low absorption and surface scattering of Ag layer. The ZAZ multilayer with 14 nm Ag film has a figure of merit up to 6.32x10{sup -2} {Omega}{sup -1}, an average transmittance over 92% and a sheet resistance of 7.1 {Omega}/sq. The results suggest that ZAZ film has better optoelectrical properties than conditional indium tin oxide single layer.

  19. Ion beam-assisted pulsed laser deposition of (Ba,Sr)(Ti,Zr)O{sub 3} films on Pt-Si substrates

    SciTech Connect

    Sakai, Joe; Vayunandana Reddy, Y. K.; Autret-Lambert, Cecile; Lagrange, Jean-Francois; Motret, Olivier; Roger, Sylvain; Wolfman, Jerome

    2011-05-15

    Ion beam-assisted pulsed laser deposition with an Ar-oxygen ion mixture was used to prepare Ba{sub 0.6}Sr{sub 0.4}Ti{sub 0.7}Zr{sub 0.3}O{sub 3} (BSTZ) thin films on Pt-coated Si substrates. The ion beam with an anode voltage of 600 V was effective to reduce the thermal budget, i.e., to achieve similar crystallinity with approximately 100 deg. C lower deposition temperature compared to the cases without ionization. It was revealed that the dielectric properties (relative dielectric constant {epsilon}{sub r} and its electric field tunability), out-of-plane lattice parameter of (001)-oriented grains (a{sub 001}), and the existence of (110)-oriented grains are correlated with one another. Elongation of a{sub 001} was suppressed, resulting in large {epsilon}{sub r} values comparable with that of a ceramic bulk of the same composition, in the BSTZ films that contain (110)-oriented grains. Less volume of amorphous BSTZ region is supposed to be playing an important role for the bulklike properties of these BSTZ films.

  20. An aberration-corrected STEM study of structural defects in epitaxial GaN thin films grown by ion beam assisted MBE.

    PubMed

    Poppitz, David; Lotnyk, Andriy; Gerlach, Jürgen W; Lenzner, Jörg; Grundmann, Marius; Rauschenbach, Bernd

    2015-06-01

    Ion-beam assisted molecular-beam epitaxy was used for direct growth of epitaxial GaN thin films on super-polished 6H-SiC(0001) substrates. The GaN films with different film thicknesses were studied using reflection high energy electron diffraction, X-ray diffraction, cathodoluminescence and primarily aberration-corrected scanning transmission electron microscopy techniques. Special attention was devoted to the microstructural characterization of GaN thin films and the GaN-SiC interface on the atomic scale. The results show a variety of defect types in the GaN thin films and at the GaN-SiC interface. A high crystalline quality of the produced hexagonal GaN thin films was demonstrated. The gained results are discussed.

  1. Effects of calcium phosphate coating to SLA surface implants by the ion-beam-assisted deposition method on self-contained coronal defect healing in dogs.

    PubMed

    Yoon, Heun-Joo; Song, Ji-Eun; Um, Yoo-Jung; Chae, Gyung Joon; Chung, Sung-Min; Lee, In-Seop; Jung, Ui-Won; Kim, Chang-Sung; Choi, Seong-Ho

    2009-08-01

    The aim of this study was to evaluate the healing of self-contained coronal defects on a sand-blasted, large-grit, acid-etched (SLA) surface implant, which had a calcium phosphate (CaP) coating applied by ion-beam-assisted deposition (IBAD). We also evaluated the effect of heating the coating to different temperatures. The CaP-coated SLA implants exhibited a slightly larger bone healing capacity in the self-contained coronal defect than SLA implants, indicating that combining SLA surface implants and a CaP coating by the IBAD method had synergistic effects on bone healing. There was no difference in the healing capacity between 350 degrees C and 450 degrees C heat treatment of the coating layer.

  2. Ion beam texturing

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    A microscopic surface texture is created by sputter etching a surface while simultaneously sputter depositing a lower sputter yield material onto the surface. A xenon ion beam source has been used to perform this texturing process on samples as large as three centimeters in diameter. Ion beam textured surface structures have been characterized with SEM photomicrographs for a large number of materials including Cu, Al, Si, Ti, Ni, Fe, Stainless steel, Au, and Ag. Surfaces have been textured using a variety of low sputter yield materials - Ta, Mo, Nb, and Ti. The initial stages of the texture creation have been documented, and the technique of ion beam sputter removal of any remaining deposited material has been studied. A number of other texturing parameters have been studied such as the variation of the texture with ion beam power, surface temperature, and the rate of texture growth with sputter etching time.

  3. Pulsed ion beam source

    DOEpatents

    Greenly, John B.

    1997-01-01

    An improved pulsed ion beam source having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center.

  4. The Influence of High-Power Ion Beams and High-Intensity Short-Pulse Implantation of Ions on the Properties of Ceramic Silicon Carbide

    NASA Astrophysics Data System (ADS)

    Kabyshev, A. V.; Konusov, F. V.; Pavlov, S. K.; Remnev, G. E.

    2016-02-01

    The paper is focused on the study of the structural, electrical and optical characteristics of the ceramic silicon carbide before and after irradiation in the regimes of the high-power ion beams (HPIB) and high-intensity short-pulse implantation (HISPI) of carbon ions. The dominant mechanism of transport of charge carriers, their type and the energy spectrum of localized states (LS) of defects determining the properties of SiC were established. Electrical and optical characteristics of ceramic before and after irradiation are determined by the biographical and radiation defects whose band gap (BG) energy levels have a continuous energetic distribution. A dominant p-type activation component of conduction with participation of shallow acceptor levels 0.05-0.16 eV is complemented by hopping mechanism of conduction involving the defects LS with a density of 1.2T017-2.4T018 eV-Am-3 distributed near the Fermi level.The effect of radiation defects with deep levels in the BG on properties change dominates after HISPI. A new material with the changed electronic structure and properties is formed in the near surface layer of SiC after the impact of the HPIB.

  5. Amorphous silicon carbonitride diaphragm for environmental-cell transmission electron microscope fabricated by low-energy ion beam induced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Matsutani, Takaomi; Yamasaki, Kayo; Imaeda, Norihiro; Kawasaki, Tadahiro

    2015-12-01

    An amorphous silicon carbonitride (a-SiCN) diaphragm for an environmental-cell transmission electron microscope (E-TEM) was fabricated by low-energy ion beam induced chemical vapor deposition (LEIBICVD) with hexamethyldisilazane (HMDSN). The films were prepared by using gaseous HMDSN and N2+ ions with energies ranging from 300 to 600 eV. The diaphragms were applied to Si (1 0 0) and a Cu grid with 100-μm-diameter holes. With increasing ion energy, these diaphragms became perfectly smooth surfaces (RMS = 0.43 nm at 600 eV), as confirmed by atomic force microscopy and TEM. The diaphragms were amorphous and transparent to 200 kV electrons, and no charge-up was observed. Fourier transform infrared spectra and X-ray photoelectron spectra revealed that the elimination of organic compounds and formation of Si-N and C-N bonds can be promoted in diaphragms by increasing the ion impact energy. The resistance to electron beams and reaction gases in the E-cell was improved when the diaphragm was formed with high ion energy.

  6. Ion beam nano-engineering of erbium doped silicon for enhanced light emission at 1.54 microns

    NASA Astrophysics Data System (ADS)

    Naczas, Sebastian

    Erbium doped silicon is of great interest as a potential light source in Silicon Photonics research due to its light emission at 1.54 mum, which corresponds to the minimal loss of optical transmission in silica fibers for telecommunications. In this thesis a basic mechanism for excitation and de-excitation of Er in Si is reviewed. Based on such fundamental understanding, an innovative approach is proposed and implemented to improve Er luminescence properties through the formation of metal nanoparticles via impurity gettering in Si nanocavities. The first part of the work demonstrates the use of ion implantation combined with thermal treatments for forming Ag nanoparticles in the vicinity of Er luminescence centers in Si. The utilization of standard semiconductor fabrication equipment and moderate thermal budgets make this approach fully compatible with Si CMOS technologies. The presence of Ag nanoparticles leads to an enhancement in the Er photoluminescence intensity, its excitation cross section and the population of optically active Er, possibly due to the surface plasmon excitation effects related to Ag nanoparticles. The resulting structures were characterized by Hydrogen depth profiling (NRA), Rutherford backscattering spectroscopy (RBS), Photoluminescence (PL), Transmission electron microscopy (TEM). In order to optimize the Er luminescence properties in such a system it is necessary to understand how the sample conditions affect the formation of Ag nanoparticles in Si. Therefore in the second part of this project we investigate the role of surface oxide in point defect generation and recombination, and the consequence on nanocavity formation and defect retention in Si. Investigation of the surface oxide effects on nanocavity formation in hydrogen implanted silicon and the influence of resultant nanocavities on diffusion and gettering of implanted silver atoms. Two sets of Si samples were prepared, depending on whether the oxide layer was etched off before

  7. Pulsed ion beam source

    DOEpatents

    Greenly, J.B.

    1997-08-12

    An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

  8. Ion-beam technologies

    SciTech Connect

    Fenske, G.R.

    1993-01-01

    This compilation of figures and diagrams reviews processes for depositing diamond/diamond-like carbon films. Processes addressed are chemical vapor deposition (HFCVD, PACVD, etc.), plasma vapor deposition (plasma sputtering, ion beam sputtering, evaporation, etc.), low-energy ion implantation, and hybrid processes (biased sputtering, IBAD, biased HFCVD, etc.). The tribological performance of coatings produced by different means is discussed.

  9. Low temperature growth of Co{sub 2}MnSi films on diamond semiconductors by ion-beam assisted sputtering

    SciTech Connect

    Nishiwaki, M.; Ueda, K. Asano, H.

    2015-05-07

    High quality Schottky junctions using Co{sub 2}MnSi/diamond heterostructures were fabricated. Low temperature growth at ∼300–400 °C by using ion-beam assisted sputtering (IBAS) was necessary to obtain abrupt Co{sub 2}MnSi/diamond interfaces. Only the Co{sub 2}MnSi films formed at ∼300–400 °C showed both saturation magnetization comparable to the bulk values and large negative anisotropic magnetoresistance, which suggests half-metallic nature of the Co{sub 2}MnSi films, of ∼0.3% at 10 K. Schottky junctions formed using the Co{sub 2}MnSi films showed clear rectification properties with rectification ratio of more than 10{sup 7} with Schottky barrier heights of ∼0.8 eV and ideality factors (n) of ∼1.2. These results indicate that Co{sub 2}MnSi films formed at ∼300–400 °C by IBAS are a promising spin source for spin injection into diamond semiconductors.

  10. Growth modes and epitaxy of FeAl thin films on a-cut sapphire prepared by pulsed laser and ion beam assisted deposition

    SciTech Connect

    Yao, Xiang; Trautvetter, Moritz; Ziemann, Paul; Wiedwald, Ulf

    2014-01-14

    FeAl films around equiatomic composition are grown on a-cut (112{sup ¯}0) sapphire substrates by ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD) at ambient temperature. Subsequent successive annealing is used to establish chemical order and crystallographic orientation of the films with respect to the substrate. We find a strongly [110]-textured growth for both deposition techniques. Pole figures prove the successful preparation of high quality epitaxial films by PLD with a single in-plane orientation. IBAD-grown films, however, exhibit three in-plane orientations, all of them with broad angular distributions. The difference of the two growth modes is attributed to the existence of a metastable intermediate crystalline orientation as concluded from nonassisted sputter depositions at different substrate temperatures. The formation of the chemically ordered crystalline B2 phase is accompanied by the expected transition from ferromagnetic to paramagnetic behavior of the films. In accordance with the different thermally induced structural recovery, we find a step-like magnetic transition to paramagnetic behavior after annealing for 1 h at T{sub A} = 300 °C for IBAD deposition, while PLD-grown films show a gradual decrease of ferromagnetic signals with rising annealing temperatures.

  11. Method for Simulating the Thickness Distribution of a Cubic Boron Nitride Film Deposited on a Curved Substrate using Ion-beam-assisted Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Valizadeh, R.; Colligon, J. S.; Kanematsu, H.; Morisato, K.

    A method for simulating the thickness distribution of cubic boron nitride (cBN) films deposited on a curved substrate using ion-beam-assisted vapor deposition (IBAD) is established and discussed. The deposition conditions are (i) boron arriving rate is 3.2 Å/s, (ii) ion current density is in the range 600-1600 μA/cm2, and (iii) gas composition fed into the ion source is 36% N2 + Ar. It was found that, due to simultaneous deposition and sputtering, the boron resputtering yield (which depends on the ion incident angle during cBN deposition) estimated from experimental data was higher than that of the boron sputtering yield of the BN films with a density of 3.482 g/cm3 calculated by the TRIM code. Using the above empirical boron resputtering yield, it is estimated that in the case of static coating, cBN films would not be formed when the incident angle is more than 40°. However, with continuous waving, the distribution of film thickness improves and the results are consistent with the experimental results. This estimation also agrees with the experimental results of discrete waving deposition within an allowable margin of error

  12. Improvement and characterization of high-reflective and anti-reflective nanostructured mirrors by ion beam assisted deposition for 944 nm high power diode laser

    NASA Astrophysics Data System (ADS)

    Ghadimi-Mahani, A.; Farsad, E.; Goodarzi, A.; Tahamtan, S.; Abbasi, S. P.; Zabihi, M. S.

    2015-11-01

    Single-layer and multi-layer coatings were applied on the surface of diode laser facets as mirrors. This thin film mirrors were designed, deposited, optimized and characterized. The effects of mirrors on facet passivation and optical properties of InGaAs/AlGaAs/GaAs diode lasers were investigated. High-Reflective (HR) and Anti-Reflective (AR) mirrors comprising of four double-layers of Al2O3/Si and a single layer of Al2O3, respectively, were designed and optimized by Macleod software for 944 nm diode lasers. Optimization of Argon flow rate was studied through Alumina thin film deposition by Ion Beam Assisted Deposition (IBAD) for mirror improvement. The nanostructured HR and AR mirrors were deposited on the front and back facet of the laser respectively, by IBAD system under optimum condition. Atomic Force Microscope (AFM), Vis-IR Spectrophotometer, Field Emission Scanning Electron Microscopy (FESEM) and laser characterization Test (P-I) were used to characterize various properties of mirrors and lasers. AFM images show mirror's root mean square roughness is nearly 1 nm. The Spectrophotometer results of the front facet transmission and the back facet reflection are in good agreement with the simulation results. Optical output power (P) versus driving current (I) characteristics, measured before and after coating the facet, revealed a significant output power enhancement due to optimized AR and HR optical coatings on facets.

  13. Vertically Free-Standing Ordered Pb(Zr0.52Ti0.48)O3 Nanocup Arrays by Template-Assisted Ion Beam Etching

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyan; Tang, Dan; Huang, Kangrong; Hu, Die; Zhang, Fengyuan; Gao, Xingsen; Lu, Xubing; Zhou, Guofu; Zhang, Zhang; Liu, Junming

    2016-04-01

    In this report, vertically free-standing lead zirconate titanate Pb(Zr0.52Ti0.48)O3 (PZT) nanocup arrays with good ordering and high density (1.3 × 1010 cm-2) were demonstrated. By a template-assisted ion beam etching (IBE) strategy, the PZT formed in the pore-through anodic aluminum oxide (AAO) membrane on the Pt/Si substrate was with a cup-like nanostructure. The mean diameter and height of the PZT nanocups (NCs) was about 80 and 100 nm, respectively, and the wall thickness of NCs was about 20 nm with a hole depth of about 80 nm. Uppermost, the nanocup structure with low aspect ratio realized vertically free-standing arrays when losing the mechanical support from templates, avoiding the collapse or bundling when compared to the typical nanotube arrays. X-ray diffraction (XRD) and Raman spectrum revealed that the as-prepared PZT NCs were in a perovskite phase. By the vertical piezoresponse force microscopy (VPFM) measurements, the vertically free-standing ordered ferroelectric PZT NCs showed well-defined ring-like piezoresponse phase and hysteresis loops, which indicated that the high-density PZT nanocup arrays could have potential applications in ultra-high non-volatile ferroelectric memories (NV-FRAM) or other nanoelectronic devices.

  14. Effect of Indium-Oxide Deposited Using an Oxygen Ion-Beam-Assisted-Deposition to Top-Emitting Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Jeong, Chang Hyun; Lim, Jong Tae; Lee, June Hee; Kim, Mi Suk; Bae, Jeong Woon; Yeom, Geun Young

    2006-10-01

    Indium oxide thin films have potential applications as cathodes in top-emitting organic light-emitting diodes (TEOLEDs). This study examined the characteristics of transparent conducting indium oxide (IO) films deposited by an oxygen ion-beam-assisted-deposition (IBAD) as a function of the applied oxygen ion energy (Va). When TEOLED devices consisting of glass/Ag (100 nm)/ITO (125 nm)/2-TNATA (30 nm)/NPB (15 nm)/Alq3 (55 nm)/LiF (1 nm)/Al (2 nm)/Au (20 nm)/IO (100 nm) were fabricated at a lower Va, a lower turn-on voltage was observed even though the maximum luminance (32,000 cd/m2) was similar one another. A Va of approximately +50 V produced an IO film with a resistivity of 8.5× 10-4 Ω\\cdotcm and a transmittance of 85%. The definition (I-V) characteristics of TEOLED devices with a cathode layer of Al (2 nm)/Au (20 nm)/IO (100 nm) were similar to the device fabricated with Al (2 nm)/Au (20 nm) only.

  15. Maskless, resistless ion beam lithography

    SciTech Connect

    Ji, Qing

    2003-03-10

    are presented. The formation of shallow pn-junctions in bulk silicon wafers by scanning focused P{sup +} beam implantation at 5 keV is also presented. With implantation dose of around 10{sup 16} cm{sup -2}, the electron concentration is about 2.5 x 10{sup 18} cm{sup -3} and electron mobility is around 200 cm{sup 2}/V{center_dot}s. To demonstrate the suitability of scanning FIB lithography for the manufacture of integrated circuit devices, SOI MOSFET fabrication using the maskless, resistless ion beam lithography is demonstrated. An array of microcolumns can be built by stacking multi-aperture electrode and insulator layers. Because the multicusp plasma source can achieve uniform ion density over a large area, it can be used in conjunction with the array of microcolumns, for massively parallel FIB processing to achieve reasonable exposure throughput.

  16. Focused ion beam system

    DOEpatents

    Leung, Ka-Ngo; Gough, Richard A.; Ji, Qing; Lee, Yung-Hee Yvette

    1999-01-01

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 .mu.m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 .mu.m or less.

  17. Focused ion beam system

    DOEpatents

    Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.

    1999-08-31

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

  18. Intense ion beam generator

    DOEpatents

    Humphries, Jr., Stanley; Sudan, Ravindra N.

    1977-08-30

    Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation.

  19. Ion beam generating apparatus

    DOEpatents

    Brown, I.G.; Galvin, J.

    1987-12-22

    An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam. 10 figs.

  20. Ion Beam Simulator

    2005-11-08

    IBSimu(Ion Beam Simulator) is a computer program for making two and three dimensional ion optical simulations. The program can solve electrostatic field in a rectangular mesh using Poisson equation using Finite Difference method (FDM). The mesh can consist of a coarse and a fine part so that the calculation accuracy can be increased in critical areas of the geometry, while most of the calculation is done quickly using the coarse mesh. IBSimu can launch ionmore » beam trajectories into the simulation from an injection surface or fomo plasma. Ion beam space charge of time independent simulations can be taken in account using Viasov iteration. Plasma is calculated by compensating space charge with electrons having Boltzmann energy distribution. The simulation software can also be used to calculate time dependent cases if the space charge is not calculated. Software includes diagnostic tools for plotting the geometry, electric field, space charge map, ion beam trajectories, emittance data and beam profiles.« less

  1. Results of a pilot study and a proposal to build a high current pulsed nanosecond low energy Si ion beam for the detection of trace amounts of heavy impurities in silicon

    SciTech Connect

    Jacobsen, F.M.; Zarcone, M.J.; Steski, D.; Smith, K.; Thieberger, P.; Lynn, K.G.; Throwe, J.; Cholewa, M. |

    1996-01-01

    Next generations of Very Large Scale Integrated circuits will require impurity contamination below 10{sup 8} atoms/cm. To detect such small quantities at or near the surface, new techniques have to be developed. The authors propose to build a high current nanosecond pulsed Si ion beam which can detect such small quantities of heavy impurities with a high mass resolution. A pilot study shows that the approach can be used to detect impurities in silicon below the 10{sup 7} atoms/cm{sup 2} level.

  2. Metal impurity-assisted formation of nanocone arrays on Si by low energy ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Steeves Lloyd, Kayla; Bolotin, Igor L.; Schmeling, Martina; Hanley, Luke; Veryovkin, Igor V.

    2016-10-01

    Fabrication of nanocone arrays on Si surfaces was demonstrated using grazing incidence irradiation with 1 keV Ar+ ions concurrently sputtering the surface and depositing metal impurity atoms on it. Among three materials compared as co-sputtering targets Si, Cu and stainless steel, only steel was found to assist the growth of dense arrays of nanocones at ion fluences between 1018 and 1019 ions/cm2. The structural characterization of samples irradiated with these ion fluences using Scanning Electron Microscopy and Atomic Force Microscopy revealed that regions far away from co-sputtering targets are covered with nanoripples, and that nanocones popped-up out of the rippled surfaces when moving closer to co-sputtering targets, with their density gradually increasing and reaching saturation in the regions close to these targets. The characterization of the samples' chemical composition with Total Reflection X-ray Fluorescence Spectrometry and X-ray Photoelectron Spectroscopy revealed that the concentration of metal impurities originating from stainless steel (Fe, Cr and Ni) was relatively high in the regions with high density of nanocones (Fe reaching a few atomic percent) and much lower (factor of 10 or so) in the region of nanoripples. Total Reflection X-ray Fluorescence Spectrometry measurements showed that higher concentrations of these impurities are accumulated under the surface in both regions. X-ray Photoelectron Spectroscopy experiments showed no direct evidence of metal silicide formation occurring on one region only (nanocones or nanoripples) and thus showed that this process could not be the driver of nanocone array formation. Also, these measurements indicated enhancement in oxide formation on regions covered by nanocones. Overall, the results of this study suggest that the difference in concentration of metal impurities in the thin near-surface layer forming under ion irradiation might be responsible for the differences in surface structures.

  3. Ion beam sputter etching

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.

    1986-01-01

    An ion beam etching process which forms extremely high aspect ratio surface microstructures using thin sputter masks is utilized in the fabrication of integrated circuits. A carbon rich sputter mask together with unmasked portions of a substrate is bombarded with inert gas ions while simultaneous carbon deposition occurs. The arrival of the carbon deposit is adjusted to enable the sputter mask to have a near zero or even slightly positive increase in thickness with time while the unmasked portions have a high net sputter etch rate.

  4. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, Graeme (Inventor)

    1984-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

  5. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1981-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

  6. Ion beam lithography system

    DOEpatents

    Leung, Ka-Ngo

    2005-08-02

    A maskless plasma-formed ion beam lithography tool provides for patterning of sub-50 nm features on large area flat or curved substrate surfaces. The system is very compact and does not require an accelerator column and electrostatic beam scanning components. The patterns are formed by switching beamlets on or off from a two electrode blanking system with the substrate being scanned mechanically in one dimension. This arrangement can provide a maskless nano-beam lithography tool for economic and high throughput processing.

  7. ITEP MEVVA ion beam for rhenium silicide production

    SciTech Connect

    Kulevoy, T.; Seleznev, D.; Kropachev, G.; Kozlov, A.; Kuibeda, R.; Yakushin, P.; Petrenko, S.; Gerasimenko, N.; Medetov, N.; Zaporozhan, O.

    2010-02-15

    The rhenium silicides are very attractive materials for semiconductor industry. In the Institute for Theoretical and Experimental Physics (ITEP) at the ion source test bench the research program of rhenium silicide production by ion beam implantation are going on. The investigation of silicon wafer after implantation of rhenium ion beam with different energy and with different total dose were carried out by secondary ions mass spectrometry, energy-dispersive x-ray microanalysis, and x-ray diffraction analysis. The first promising results of rhenium silicide film production by high intensity ion beam implantation are presented.

  8. Heavy ion beam probing

    SciTech Connect

    Hickok, R L

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included.

  9. Introduction to Ion Beam Therapy

    SciTech Connect

    Martisikova, Maria

    2010-01-05

    Presently, ion beam therapy reaches an increasing interest within the field of radiation therapy, which is caused by the promising clinical results obtained in the last decades. Ion beams enable higher dose conformation to the tumor and increased sparing of the surrounding tissue in comparison to the standard therapy using high energy photons. Heavy ions, like carbon, offer in addition increased biological effectiveness, which makes them suitable for treatment of radioresistant tumors. This contribution gives an overview over the physical and biological properties of ion beams. Common fundamental principles of ion beam therapy are summarized and differences between standard therapy with high energy photons, proton and carbon ion therapy are discussed. The technologies used for the beam production and delivery are introduced, with emphasis to the differences between passive and active beam delivery systems. The last part concentrates on the quality assurance in ion therapy. Specialties of dosimetry in medical ion beams are discussed.

  10. Helicon plasma generator-assisted surface conversion ion source for the production of H- ion beams at the Los Alamos Neutron Science Centera)

    NASA Astrophysics Data System (ADS)

    Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J.

    2008-02-01

    The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H- ion beams in a filament-driven discharge. In this kind of an ion source the extracted H- beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H- converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H- ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H- ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H- production (main discharge) in order to further improve the brightness of extracted H- ion beams.

  11. Helicon plasma generator-assisted surface conversion ion source for the production of H(-) ion beams at the Los Alamos Neutron Science Center.

    PubMed

    Tarvainen, O; Rouleau, G; Keller, R; Geros, E; Stelzer, J; Ferris, J

    2008-02-01

    The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H(-) ion beams in a filament-driven discharge. In this kind of an ion source the extracted H(-) beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H(-) converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H(-) ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H(-) ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H(-) production (main discharge) in order to further improve the brightness of extracted H(-) ion beams.

  12. Ion beam sputtering of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Sovey, J. S.

    1978-01-01

    Etching and deposition of fluoropolymers are of considerable industrial interest for applications dealing with adhesion, chemical inertness, hydrophobicity, and dielectric properties. This paper describes ion beam sputter processing rates as well as pertinent characteristics of etched targets and films. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Also presented are sputter target and film characteristics which were documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs.

  13. Applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Gelerinter, E.; Spielberg, N.

    1980-01-01

    Wire adhesion in steel belted radial tires; carbon fibers and composite; cold welding, brazing, and fabrication; hydrogen production, separation, and storage; membrane use; catalysis; sputtering and texture; and ion beam implantation are discussed.

  14. Ion Beam Modification of Materials

    SciTech Connect

    Averback, B; de la Rubia, T D; Felter, T E; Hamza, A V; Rehn, L E

    2005-10-10

    This volume contains the proceedings of the 14th International Conference on Ion Beam Modification of Materials, IBMM 2004, and is published by Elsevier-Science Publishers as a special issue of Nuclear Instruments and Methods B. The conference series is the major international forum to present and discuss recent research results and future directions in the field of ion beam modification, synthesis and characterization of materials. The first conference in the series was held in Budapest, Hungary, 1978, and subsequent conferences were held every two years at locations around the Globe, most recently in Japan, Brazil, and the Netherlands. The series brings together physicists, materials scientists, and ion beam specialists from all over the world. The official conference language is English. IBMM 2004 was held on September 5-10, 2004. The focus was on materials science involving both basic ion-solid interaction processes and property changes occurring either during or subsequent to ion bombardment and ion beam processing in relation to materials and device applications. Areas of research included Nanostructures, Multiscale Modeling, Patterning of Surfaces, Focused Ion Beams, Defects in Semiconductors, Insulators and Metals, Cluster Beams, Radiation Effects in Materials, Photonic Devices, Ion Implantation, Ion Beams in Biology and Medicine including New Materials, Imaging, and Treatment.

  15. Nanopatterning of metal-coated silicon surfaces via ion beam irradiation: Real time x-ray studies reveal the effect of silicide bonding

    SciTech Connect

    El-Atwani, Osman; Gonderman, Sean; Suslova, Anastassiya; Fowler, Justin; El-Atwani, Mohamad; DeMasi, Alexander; Ludwig, Karl; Paul Allain, Jean

    2013-03-28

    We investigated the effect of silicide formation on ion-induced nanopatterning of silicon with various ultrathin metal coatings. Silicon substrates coated with 10 nm Ni, Fe, and Cu were irradiated with 200 eV argon ions at normal incidence. Real time grazing incidence small angle x-ray scattering (GISAXS) and x-ray fluorescence (XRF) were performed during the irradiation process and real time measurements revealed threshold conditions for nanopatterning of silicon at normal incidence irradiation. Three main stages of the nanopatterning process were identified. The real time GISAXS intensity of the correlated peaks in conjunction with XRF revealed that the nanostructures remain for a time period after the removal of the all the metal atoms from the sample depending on the binding energy of the metal silicides formed. Ex-situ XPS confirmed the removal of all metal impurities. In-situ XPS during the irradiation of Ni, Fe, and Cu coated silicon substrates at normal incidence demonstrated phase separation and the formation of different silicide phases that occur upon metal-silicon mixing. Silicide formation leads to nanostructure formation due the preferential erosion of the non-silicide regions and the weakening of the ion induced mass redistribution.

  16. Controllable laser ion beam generation

    NASA Astrophysics Data System (ADS)

    Kamiyama, D.; Takano, M.; Nagashima, T.; Barada, D.; Gu, Y. J.; Li, X. F.; Kong, Q.; Wang, P. X.; Kawata, S.

    2016-05-01

    In intense-laser plasma interaction, several issues still remain to be solved for a future laser particle acceleration. In this paper we focus on a bunching of ion beam, which is preaccelerated by a strong electric field generated in a laser plasma interaction. In this study, a nearcritical-density plasma target is illuminated by an intense short laser pulse. A moving strong inductive electric field is generated inside of the target. We have successfully obtained a bunched ion beam in our particle-in-cell simulations in this paper.

  17. Production and characterization of ion beams from magnetically insulated diodes

    SciTech Connect

    Neri, J.M.

    1982-01-01

    The operation of magnetically insulated diodes and the characteristics of the resulting ion beams have been investigated using two pulsed power generators, LYNX at the 10/sup 9/W power level, and Neptune at the 10/sup 11/W power level. LYNX is a small magnetically insulated diode driven directly by a Marx bank. By changing the material used as the surface flashover ion source, the majority ion species generated by the diode could be chosen. Ion beams produced so far by this device are: protons, lithium, boron, carbon, sodium, strontium, and barium. Typical beam parameters for the ion beams are peak energies of 300 keV, current densities of 40 to 60 A/cm/sup 2/, and pulse durations of 300 to 400 nsec. The ion beam uniformity, divergence, and reproducibility were shown to be a function of the surface flashover source geometry. Finally, the LYNX ion beam was also used to anneal silicon crystals and other materials science experiments. The diode used on the Neptune generator was designed to study virtual cathode formation in a high power magnetically insulated diode. The physical cathode was replaced by electrons that ExB drift on the applied magnetic field lines. It was found that the best electrode configuration is one in which the electrons are required to only undergo the Hall drift to form the cathode. The divergence of the ion beam was examined with time-dependent and time-integrated shadowbox diagnostics. It was found that the intrinsic divergence of the ion beam does not have a strong directional dependence.

  18. Focused ion beams in biology.

    PubMed

    Narayan, Kedar; Subramaniam, Sriram

    2015-11-01

    A quiet revolution is under way in technologies used for nanoscale cellular imaging. Focused ion beams, previously restricted to the materials sciences and semiconductor fields, are rapidly becoming powerful tools for ultrastructural imaging of biological samples. Cell and tissue architecture, as preserved in plastic-embedded resin or in plunge-frozen form, can be investigated in three dimensions by scanning electron microscopy imaging of freshly created surfaces that result from the progressive removal of material using a focused ion beam. The focused ion beam can also be used as a sculpting tool to create specific specimen shapes such as lamellae or needles that can be analyzed further by transmission electron microscopy or by methods that probe chemical composition. Here we provide an in-depth primer to the application of focused ion beams in biology, including a guide to the practical aspects of using the technology, as well as selected examples of its contribution to the generation of new insights into subcellular architecture and mechanisms underlying host-pathogen interactions.

  19. ION BEAM COLLIMATOR

    DOEpatents

    Langsdorf, A.S. Jr.

    1957-11-26

    A device is described for defining a beam of high energy particles wherein the means for defining the beam in the horizontal and vertical dimension are separately adjustable and the defining members are internally cooled. In general, the device comprises a mounting block having a central opening through which the beam is projected, means for rotatably supporting two pairs of beam- forming members, passages in each member for the flow of coolant; the beam- forming members being insulated from each other and the block, and each having an end projecting into the opening. The beam-forming members are adjustable and may be cooperatively positioned to define the beam passing between the end of the members. To assist in projecting and defining the beam, the member ends have individual means connected thereto for indicating the amount of charge collected thereon due to beam interception.

  20. Synthesis and characterization of titanium carbide, titanium boron carbonitride, titanium boride/titanium carbide and titanium carbide/chromium carbide multilayer coatings by reactive and ion beam assisted, electron beam-physical vapor deposition (EB-PVD)

    NASA Astrophysics Data System (ADS)

    Wolfe, Douglas Edward

    The purpose of the present work was to investigate the synthesis of titanium carbide, TiBCN, TiB2/TiC and TiC/Cr23C6 multilayer coatings by several methods of electron beam-physical vapor deposition (EB-PVD) and examine the affects of various processing parameters on the properties and microstructures of the coatings. TiC was successfully deposited by reactive ion beam assisted (RIBA), EB-PVD and the results were compared to various titanium carbide coatings deposited by a variety of techniques. The affects of substrate temperature and ion beam current density were correlated with composition, hardness, changes in the lattice parameter, degree of crystallographic texture, residual stress, surface morphology, and microstructure. The average Vicker's hardness number was found to increase with increasing ion beam current density and increase over the substrate temperature range of 250°C to 650°C. The average Vicker's hardness number decreased at a substrate temperature of 750°C as a result of texturing and microstructure. The present investigation shows that the average Vicker's hardness number is not only a function of the composition, but also the microstructure including the degree of crystallographic texture. TiB2/TiC multilayer coatings were deposited by argon ion beam assisted, EB-PVD with varying number of total layers to two different film thicknesses under slightly different deposition conditions. In both cases, the hardness of the coatings increased with increasing number of total layers. The adhesion of the coatings ranged from 30 N to 50 N, with the better adhesion values obtained with the thinner coatings. The crystallographic texture coefficients of both the TiC and TiB2 layers were found to change with increasing number of total layers. The multilayer design was found to significantly affect the microstructure and grain size of the deposited coatings. The fracture toughness was found to decrease with increasing number of total layers and was

  1. Ion-beam Plasma Neutralization Interaction Images

    SciTech Connect

    Igor D. Kaganovich; Edward Startsev; S. Klasky; Ronald C. Davidson

    2002-04-09

    Neutralization of the ion beam charge and current is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because the excitation of nonlinear plasma waves may occur. Computer simulation images of plasma neutralization of the ion beam pulse are presented.

  2. Ion beam microtexturing of surfaces

    NASA Technical Reports Server (NTRS)

    Robinson, R. S.

    1981-01-01

    Some recent work in surface microtecturing by ion beam sputtering is described. The texturing is accomplished by deposition of an impurity onto a substrate while simultaneously bombarding it with an ion beam. A summary of the theory regarding surface diffusion of impurities and the initiation of cone formation is provided. A detailed experimental study of the time-development of individual sputter cones is described. A quasi-liquid coating was observed that apparently reduces the sputter rate of the body of a cone compared to the bulk material. Experimental measurements of surface diffusion activation energies are presented for a variety of substrate-seed combinations and range from about 0.3 eV to 1.2 eV. Observations of apparent crystal structure in sputter cones are discussed. Measurements of the critical temperature for cone formation are also given along with a correlation of critical temperature with substrate sputter rate.

  3. Ion beam probe diagnostic system

    NASA Astrophysics Data System (ADS)

    Hickok, R. L.; Jennings, W. C.; Woo, J. T.; Connor, K. A.

    1980-07-01

    Tokomak plasmas suitable for diagnostic development were produced in RENTOR following technological improvements in the vacuum chamber and discharge cleaning systems. Secondary ion signals were obtained from the heavy ion beam probe on RENTOR leading to initial estimates of the plasma space potential, which appears to vary by several hundred volts during the plasma pulse. The principle of measuring space potential in a minimum-B geometry was established using an ion gun mounted at the center of the ALEX baseball coil. The neutral beam probe was installed for measuring the space potential using actual secondary ion signals from a hollow cathode arc in ALEX and preliminary tests have begun. The ion beam test stand was significantly altered to allow more flexibility in testing energy analyzers, ion guns, and ion focusing concepts.

  4. Ion beam inertial confinement target

    DOEpatents

    Bangerter, Roger O.; Meeker, Donald J.

    1985-01-01

    A target for implosion by ion beams composed of a spherical shell of frozen DT surrounded by a low-density, low-Z pusher shell seeded with high-Z material, and a high-density tamper shell. The target has various applications in the inertial confinement technology. For certain applications, if desired, a low-density absorber shell may be positioned intermediate the pusher and tamper shells.

  5. Triple ion beam irradiation facility

    SciTech Connect

    Lewis, M.B.; Allen, W.R.; Buhl, R.A.; Packan, N.H.; Cook, S.W.; Mansur, L.K.

    1988-12-01

    A unique ion irradiation facility consisting of three accelerators is described. The accelerators can be operated simultaneously to deliver three ion beams on one target sample. The energy ranges of the ions are 50 to 400 keV, 200 keV to 2.5 MeV, and 1.0 to 5.0 MeV. Three different ions in the appropriate mass range can be simultaneously implanted to the same depth in a target specimen as large as 100 mm/sup 2/ in area. Typical depth ranges are 0.1 to 1.0 ..mu..m. The X-Y profiles of all three ion beams are measured by a system of miniature Faraday cups. The low-voltage accelerator can periodically ramp the ion beam energy during the implantation. Three different types of target chambers are in use at this facility. The triple-beam high-vacuum chamber can hold nine transmission electron microscopy specimens at elevated temperature during a irradiation by the three simultaneous beams. A second high-vacuum chamber on the medium-voltage accelerator beamline houses a low- and high-temperature translator and a two-axis goniometer for ion channeling measurements. The third chamber on the high-energy beamline can be gas-filled for special stressed specimen irradiations. Special applications for the surface modification of materials with this facility are described. Appendixes containing operating procedures are also included. 18 refs., 27 figs., 1 tab.

  6. Metal assisted anodic etching of silicon.

    PubMed

    Lai, Chang Quan; Zheng, Wen; Choi, W K; Thompson, Carl V

    2015-07-01

    Metal assisted anodic etching (MAAE) of Si in HF, without H2O2, is demonstrated. Si wafers were coated with Au films, and the Au films were patterned with an array of holes. A Pt mesh was used as the cathode while the anodic contact was made through either the patterned Au film or the back side of the Si wafer. Experiments were carried out on P-type, N-type, P(+)-type and N(+)-type Si wafers and a wide range of nanostructure morphologies were observed, including solid Si nanowires, porous Si nanowires, a porous Si layer without Si nanowires, and porous Si nanowires on a thick porous Si layer. Formation of wires was the result of selective etching at the Au-Si interface. It was found that when the anodic contact was made through P-type or P(+)-type Si, regular anodic etching due to electronic hole injection leads to formation of porous silicon simultaneously with metal assisted anodic etching. When the anodic contact was made through N-type or N(+)-type Si, generation of electronic holes through processes such as impact ionization and tunnelling-assisted surface generation were required for etching. In addition, it was found that metal assisted anodic etching of Si with the anodic contact made through the patterned Au film essentially reproduces the phenomenology of metal assisted chemical etching (MACE), in which holes are generated through metal assisted reduction of H2O2 rather than current flow. These results clarify the linked roles of electrical and chemical processes that occur during electrochemical etching of Si. PMID:26059556

  7. High temperature coefficient of resistance achieved by ion beam assisted sputtering with no heat treatment in V{sub y}M{sub 1−y}O{sub x} (M = Nb, Hf)

    SciTech Connect

    Vardi, Naor; Sharoni, Amos

    2015-11-15

    Thermal imaging based on room temperature bolometer sensors is a growing market, constantly searching for improved sensitivity. One important factor is the temperature coefficient of resistance (TCR), i.e., the sensitivity of the active material. Herein, the authors report the improved TCR properties attainable by the “ion beam assisted deposition” method for room temperature deposition. V{sub y}M{sub 1−y}O{sub x} (M = Nb, Hf) thin-film alloys were fabricated on 1 μm thermal SiO{sub 2} atop Si (100) substrates by reactive magnetron cosputtering at room temperature using a low energy ion source, aimed at the film, to insert dissociated oxygen species and increase film density. The authors studied the influence of deposition parameters such as oxygen partial pressure, V to M ratio, and power of the plasma source, on resistance and TCR. The authors show high TCR (up to −3.7% K{sup −1}) at 300 K, and excellent uniformity, but also an increase in resistance. The authors emphasize that samples were prepared at room temperature with no heat treatment, much simpler than common processes that require annealing at high temperatures. So, this is a promising fabrication route for uncooled microbolometers.

  8. Ion beam texturing of surfaces

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.; Robinson, R. S.

    1979-01-01

    Textured surfaces, typically with conical structures, have been produced previously by simultaneously etching a surface and seeding that surface with another material. A theory based on surface diffusion predicts a variation in cone spacing with surface temperature, as well as a critical temperature below which cones will not form. Substantial agreement with theory has been found for several combinations of seed and surface materials, including one with a high sputter yield seed on a low sputter yield surface (gold on aluminum). Coning with this last combination was predicted by the theory for a sufficiently mobile seed material. The existence of a minimum temperature for the formation of cones should also be important to those interested in ion-beam machining smooth surfaces. Elements contained in the environmental contaminants or in the sputtered alloys or compounds may serve as seed material.

  9. Implementation of ion-beam techniques in microsystems manufacturing: opportunities in cell biology

    NASA Astrophysics Data System (ADS)

    Campo, E. M.; Lopez-Martinez, M. J.; Fernández, E.; Esteve, J..; Plaza, J. A.

    2009-05-01

    Micromachining techniques are proposed to mass-manufacture innovative silicon oxide micropipettes and conventional boron-silicate pipettes with highly customized tips to address increasingly demanding cell handling procedures. Cell handling has become a crucial procedure in cell biology, especially in nuclear transfer, DNA injection, and in assisted reproductive techniques. Most pipette manufacturing procedures involve tedious artisanal methods prone to failure and with limited functionality. We expect high tip customization to have a large impact in current and future cell manipulation, paving the way for augmented functionality. Although proper biocompatibility assessments remain to be explored, initial pierced embryos are seen to continue their division procedure up to at least 24 hours. The continued cellular division is a good sign of biocompatibility. These results suggest that residual chemical agents or gallium ions injected during milling could be harmless to life development. We conclude that we have produced a novel technique combining microfabrication and Focus Ion Beam processes with great potential for industrial applications.

  10. ION BEAM FOCUSING MEANS FOR CALUTRON

    DOEpatents

    Backus, J.G.

    1959-06-01

    An ion beam focusing arrangement for calutrons is described. It provides a virtual focus of origin for the ion beam so that the ions may be withdrawn from an arc plasma of considerable width providing greater beam current and accuracy. (T.R.H.)

  11. New apparatus increases ion beam power density

    NASA Technical Reports Server (NTRS)

    Baldwin, L. V.; Sandborn, V. A.

    1964-01-01

    To increase ion engine or rocket power, an ion source and emitter, an ion beam focusing electrode, and an ion accelerator are incorporated into the system. In operation the space charge surrounding the ion emitter decreases, the ion beam density accelerates, and engine power increases.

  12. Ion-Beam Analysis of Airborne Pollution

    NASA Astrophysics Data System (ADS)

    Harrington, Charles; Gleason, Colin; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Labrake, Scott; Vineyard, Michael

    2010-11-01

    An undergraduate laboratory research program in ion-beam analysis (IBA) of atmospheric aerosols is being developed to study pollution in the Capitol District and Adirondack Mountains of New York. The IBA techniques applied in this project include proton induced X-ray emission (PIXE), proton induced gamma-ray emission (PIGE), Rutherford backscattering (RBS), and proton elastic scattering analysis (PESA). These methods are well suited for studying air pollution because they are quick, non-destructive, require little to no sample preparation, and capable of investigating microscopic samples. While PIXE spectrometry is used to analyze most elements from silicon to uranium, the other techniques are being applied to measure some of the remaining elements and complement PIXE in the study of aerosols. The airborne particulate matter is collected using nine-stage cascade impactors that separate the particles according to size and the samples are bombarded with proton beams from the Union College 1.1-MV Pelletron Accelerator. The reaction products are measured with SDD X-ray, Ge gamma-ray, and Si surface barrier charged particle detectors. Here we report on the progress we have made on the PIGE, RBS, and PESA analysis of aerosol samples.

  13. Microstructural evolution during ion beam assisted deposition

    SciTech Connect

    Hubler, G.K.

    1995-12-31

    The advantages of energetic deposition are low temperature processing, oriented or single crystal films, high phase purity, high density and good adhesion to substrates. The time and spatial scales over which the atoms arrange themselves on a surface are not easy accessed experimentally. Therefore, these advantages are customarily verified by ex-situ examination of films after deposition is complete, which gives little information on atomic scale processes that lead to the listed advantages. The addition of energy to the deposition flux effects surface processes that are otherwise only controllable by changing the substrate temperature. Thus, understanding the mechanisms by which energetic atoms alter surface processes in analogy with thermal effects is of paramount interest for optimization of the deposition parameters. This review summarizes the state of knowledge on the effects of energetic ions on film formation. For high quality, defect free films, the energy must be controlled in the energy region of 5 eV to 30 eV. Below about 5 eV, the energy is ineffective for changing the physical processes, and above about 30 eV, defects are added to the film by displacement damage that cannot anneal out due to low temperature of the deposition. Models for the composition and chemistry of films energetically deposited are progressing well, while models for prediction of the phases that form are almost nonexistent. Molecular dynamics provide the best information, but only a handful of cases have been simulated.

  14. Self-neutralized ion beam

    SciTech Connect

    Salvadori, M. C.; Teixeira, F. S.; Nikolaev, A.; Savkin, K. P.; Oks, E. M.; Spaedtke, P.; Yu, K. M.; Brown, I. G.

    2011-10-15

    A vacuum arc ion source provides high current beams of metal ions that have been used both for accelerator injection and for ion implantation, and in both of these applications the degree of space charge neutralization of the beam is important. In accelerator injection application, the beam from the ion source may be accelerated further (post-acceleration), redirected by a bending magnet(s), or focused with magnetic or electrostatic lenses, and knowledge of the beam space charge is needed for optimal design of the optical elements. In ion implantation application, any build-up of positive charge in the insulating targets must be compensated by a simultaneous flux of cold electrons so as to provide overall charge neutrality of the target. We show that in line-of-sight ion implantation using a vacuum arc ion source, the high current ion beam carries along its own background sea of cold electrons, and this copious source of electrons provides a ''self-neutralizing'' feature to the beam. Here we describe experiments carried out in order to demonstrate this effect, and we provide an analysis showing that the beam is space-charge-neutralized to a very high degree.

  15. Silicon sheets by redox assisted chemical exfoliation.

    PubMed

    Tchalala, Mohamed Rachid; Ali, Mustapha Ait; Enriquez, Hanna; Kara, Abdelkader; Lachgar, Abdessadek; Yagoubi, Said; Foy, Eddy; Vega, Enrique; Bendounan, Azzedine; Silly, Mathieu G; Sirotti, Fausto; Nitshe, Serge; Chaudanson, Damien; Jamgotchian, Haik; Aufray, Bernard; Mayne, Andrew J; Dujardin, Gérald; Oughaddou, Hamid

    2013-11-01

    In this paper, we report the direct chemical synthesis of silicon sheets in gram-scale quantities by chemical exfoliation of pre-processed calcium disilicide (CaSi2). We have used a combination of x-ray photoelectron spectroscopy, transmission electron microscopy and energy-dispersive x-ray spectroscopy to characterize the obtained silicon sheets. We found that the clean and crystalline silicon sheets show a two-dimensional hexagonal graphitic structure. PMID:24131870

  16. Kinetic Simulations of Ion Beam Neutralization

    SciTech Connect

    Wang, Joseph

    2010-05-21

    Ion beam emission/neutralization is one of the most fundamental problems in spacecraft plasma interactions and electric propulsion. Although ion beam neutralization is readily achieved in experiments, the understanding of the underlying physical process remains at a rather primitive level. No theoretical or simulation models have convincingly explained the detailed neutralization mechanism, and no conclusions have been reached. This paper presents a fully kinetic simulation of ion beam neutralization and plasma beam propagation and discusses the physics of electron-ion coupling and the resulting propagation of a neutralized mesothermal plasma.

  17. Development of polyatomic ion beam system using liquid organic materials

    NASA Astrophysics Data System (ADS)

    Takaoka, G. H.; Nishida, Y.; Yamamoto, T.; Kawashita, M.

    2005-08-01

    We have developed a new type of polyatomic ion beam system using liquid organic materials such as octane and ethanol, which consists of a capillary type of nozzle, an ionizer, a mass-separator and a substrate holder. Ion current extracted after ionization was 430 μA for octane and 200 μA for ethanol, respectively. The mass-analysis was realized using a compact E × B mass filter, and the mass-analyzed ion beams were transferred toward the substrate. The ion current density at the substrate was a few μA/cm2 for the mass-separated ion species. Interactions of polyatomic ion beams with silicon (Si) surfaces were investigated by utilizing the ellipsometry measurement. It was found that the damaged layer thickness irradiated by the polyatomic ions with a mass number of about 40 was smaller than that by Ar ion irradiation at the same incident energy and ion fluence. The result indicated that the rupture of polyatomic ions occurred upon its impact on the Si surface with an incident energy larger than a few keV. In addition, the chemical modification of Si surfaces such as wettability could be achieved by adjusting the incident energy for the ethanol ions, which included all the fragment ions.

  18. Ion Beam Bombardment of Biological Tissue

    NASA Astrophysics Data System (ADS)

    Sangyuenyongpipat, S.; Yu, L. D.; Vilaithong, T.; Phanchaisri, B.; Anuntalabhochai, S.; Brown, I. G.

    2003-10-01

    While ion implantation has become a well-established technique for the surface modification of inorganic materials, the ion bombardment of cellular tissue has received little research attention. A program in ion beam bioengineering has been initiated at Chiang Mai University, and the ion beam induced transfer of plasmid DNA molecules into bacterial cells (E. coli) has been demonstrated. Subsequent work has been directed toward exploration of ion beam bombardment of plant cells in an effort to understand the possible mechanisms involved in the DNA transfer. In particular, ion beam bombardment of onion cells was carried out and the effects investigated. Among the novel features observed is the formation of "microcraters" - sub-micron surface features that could provide a pathway for the transfer of large molecules into the interior cell region. Here we describe our onion skin ion bombardment investigations.

  19. Biomedical applications of ion-beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Gibbons, D. F.; Vankampen, C. L.; Babbush, C. A.

    1979-01-01

    Microscopically-rough surface texture of various biocompatible alloys and polymers produced by ion-beam sputtering may result in improvements in response of hard or soft tissue to various surgical implants.

  20. Neurosurgical applications of ion beams

    NASA Astrophysics Data System (ADS)

    Fabrikant, Jacob I.; Levy, Richard P.; Phillips, Mark H.; Frankel, Kenneth A.; Lyman, John T.

    1989-04-01

    The program at Donner Pavilion has applied nuclear medicine research to the diagnosis and radiosurgical treatment of life-threatening intracranial vascular disorders that affect more than half a million Americans. Stereotactic heavy-charged-particle Bragg peak radiosurgery, using narrow beams of heavy ions, demonstrates superior biological and physical characteristics in brain over X-and γ-rays, viz., improved dose distribution in the Bragg peak and sharp lateral and distal borders and less scattering of the beam. Examination of CNS tissue response and alteration of cerebral blood-flow dynamics related to heavy-ion Bragg peak radiosurgery is carried out using three-dimensional treatment planning and quantitative imaging utilizing cerebral angiography, computerized tomography (CT), magnetic resonance imaging (MRI), cine-CT, xenon X-ray CT and positron emission tomography (PET). Also under examination are the physical properties of narrow heavy-ion beams for improving methods of dose delivery and dose distribution and for establishing clinical RBE/LET and dose-response relationships for human CNS tissues. Based on the evaluation and treatment with stereotactically directed narrow beams of heavy charged particles of over 300 patients, with cerebral angiography, CT scanning and MRI and PET scanning of selected patients, plus extensive clinical and neuroradiological followup, it appears that Stereotactic charged-particle Bragg peak radiosurgery obliterates intracranial arteriovenous malformations or protects against rebleeding with reduced morbidity and no mortality. Discussion will include the method of evaluation, the clinical research protocol, the Stereotactic neuroradiological preparation, treatment planning, the radiosurgery procedure and the protocol for followup. Emphasis will be placed on the neurological results, including the neuroradiological and clinical response and early and late delayed injury in brain leading to complications (including vasogenic edema

  1. Ion Beam Therapy in Europe

    NASA Astrophysics Data System (ADS)

    Kraft, Gerhard

    2009-03-01

    At present, seven facilities in Europe treat deep-seated tumors with particle beams, six with proton beams and one with carbon ions. Three of these facilities are in Moscow, St. Petersburg and Dubna, Russia. Other facilities include the TSL Uppsala, Sweden, CPO Orsay, France, and PSI Villigen, Switzerland, all for proton therapy, and GSI, Darmstadt, Germany, which utilizes carbon ions only. But only two of these facilities irradiate with scanned ion beams: the Paul Scherer Institute (PSI), Villigen (protons) and the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. These two facilities are experimental units within physics laboratories and have developed the technique of intensity-modulated beam scanning in order to produce irradiation conforming to a 3-D target. There are three proton centers presently under construction in Munich, Essen and Orsay, and the proton facility at PSI has added a superconducting accelerator connected to an isocentric gantry in order to become independent of the accelerator shared with the physics research program. The excellent clinical results using carbon ions at National Institute of Radiological Science (NIRS) in Chiba and GSI have triggered the construction of four new heavy-ion therapy projects (carbon ions and protons), located in Heidelberg, Pavia, Marburg and Kiel. The projects in Heidelberg and Pavia will begin patient treatment in 2009, and the Marburg and Kiel projects will begin in 2010 and 2011, respectively. These centers use different accelerator designs but have the same kind of treatment planning system and use the same approach for the calculation of the biological effectiveness of the carbon ions as developed at GSI [1]. There are many other planned projects in the works. Do not replace the word "abstract," but do replace the rest of this text. If you must insert a hard line break, please use Shift+Enter rather than just tapping your "Enter" key. You may want to print this page and refer to it as a style

  2. Computer simulation of ion beam analysis of laterally inhomogeneous materials

    NASA Astrophysics Data System (ADS)

    Mayer, M.

    2016-03-01

    The program STRUCTNRA for the simulation of ion beam analysis charged particle spectra from arbitrary two-dimensional distributions of materials is described. The code is validated by comparison to experimental backscattering data from a silicon grating on tantalum at different orientations and incident angles. Simulated spectra for several types of rough thin layers and a chessboard-like arrangement of materials as example for a multi-phase agglomerate material are presented. Ambiguities between back-scattering spectra from two-dimensional and one-dimensional sample structures are discussed.

  3. Ion beam processing of advanced electronic materials

    SciTech Connect

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B.; International Business Machines Corp., Yorktown Heights, NY . Thomas J. Watson Research Center; Oak Ridge National Lab., TN )

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

  4. Ion beam microtexturing and enhanced surface diffusion

    NASA Technical Reports Server (NTRS)

    Robinson, R. S.

    1982-01-01

    Ion beam interactions with solid surfaces are discussed with particular emphasis on microtexturing induced by the deliberate deposition of controllable amounts of an impurity material onto a solid surface while simultaneously sputtering the surface with an ion beam. Experimental study of the optical properties of microtextured surfaces is described. Measurements of both absorptance as a function of wavelength and emissivity are presented. A computer code is described that models the sputtering and ion reflection processes involved in microtexture formation.

  5. Mass spectrometer and methods of increasing dispersion between ion beams

    DOEpatents

    Appelhans, Anthony D.; Olson, John E.; Delmore, James E.

    2006-01-10

    A mass spectrometer includes a magnetic sector configured to separate a plurality of ion beams, and an electrostatic sector configured to receive the plurality of ion beams from the magnetic sector and increase separation between the ion beams, the electrostatic sector being used as a dispersive element following magnetic separation of the plurality of ion beams. Other apparatus and methods are provided.

  6. Ion Beam Micro-Sculpturing

    NASA Astrophysics Data System (ADS)

    Kubby, Joel Alan

    Unique experimental observations are reported on the quasi-dynamic evolution of surface morphology during sputter erosion on two different length scales. The results provide qualitative confirmation of current first and second order approximation theories of cone evolution. On a length scale that is large in comparison to the incident ions projected range R(,p)(E) within a target matrix, experimental observations using the Scanning Electron Microscopy (SEM) show the initiation and temporal development of sputter induced morphology that can be explained by the variation of sputter efficiency with angle of ion incidence. On a length scale of ion penetration depth, typically 5 to 20 nm, the unique target configuration used in our experiments allows a high resolution study to be performed by Transmission Electron Microscopy (TEM) that reveals changes in surface topography on the 10's of nanometers length scale. The first high resolution TEM observations of a sputter induced cone show a reduced sputter yield within a distance of R(,p)(E) of the cone apex. These experimental observations support mechanisms that link the events taking place on an atomic length scale within the atomic collision cascade with those features that are predicted by first order erosion theory. Previous experimental SEM observations had concentrated on the enhanced erosion predicted by this mechanism at the base of a cone. However results in this basal region are also influenced by secondary (recoil) sputtering that obscures experimental confirmation of these cascade density effects. Qualitative agreement between the observed surface evolution and analytical analysis using computer simulations on both length scales allows these analytical tools, in conjunction with a model of the erosion (and accretion) processes, to be used to physically control surface evolution in a useful manner. This ion beam sculpturing technique is used to produce field emitters for application to charged particle sources

  7. Metal-assisted chemical etch porous silicon formation method

    DOEpatents

    Li, Xiuling; Bohn, Paul W.; Sweedler, Jonathan V.

    2004-09-14

    A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a silicon surface. The surface is then etched in a solution including HF and an oxidant for a brief period, as little as a couple seconds to one hour. A preferred oxidant is H.sub.2 O.sub.2. Morphology and light emitting properties of porous silicon can be selectively controlled as a function of the type of metal deposited, Si doping type, silicon doping level, and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

  8. Imaging Nanophotonic Modes of Microresonators using a Focused Ion Beam

    PubMed Central

    Twedt, Kevin A.; Zou, Jie; Davanco, Marcelo; Srinivasan, Kartik; McClelland, Jabez J.; Aksyuk, Vladimir A.

    2016-01-01

    Optical microresonators have proven powerful in a wide range of applications, including cavity quantum electrodynamics1–3, biosensing4, microfludics5, and cavity optomechanics6–8. Their performance depends critically on the exact distribution of optical energy, confined and shaped by the nanoscale device geometry. Near-field optical probes9 can image this distribution, but the physical probe necessarily perturbs the near field, which is particularly problematic for sensitive high quality factor resonances10,11. We present a new approach to mapping nanophotonic modes that uses a controllably small and local optomechanical perturbation introduced by a focused lithium ion beam12. An ion beam (radius ≈50 nm) induces a picometer-scale dynamic deformation of the resonator surface, which we detect through a shift in the optical resonance wavelength. We map five modes of a silicon microdisk resonator (Q≥20,000) with both high spatial and spectral resolution. Our technique also enables in-situ observation of ion implantation damage and relaxation dynamics in a silicon lattice13,14. PMID:27087832

  9. Intense non-relativistic cesium ion beam

    SciTech Connect

    Lampel, M.C.

    1984-02-01

    The Heavy Ion Fusion group at Lawrence Berkeley Laboratory has constructed the One Ampere Cesium Injector as a proof of principle source to supply an induction linac with a high charge density and high brightness ion beam. This is studied here. An electron beam probe was developed as the major diagnostic tool for characterizing ion beam space charge. Electron beam probe data inversion is accomplished with the EBEAM code and a parametrically adjusted model radial charge distribution. The longitudinal charge distribution was not derived, although it is possible to do so. The radial charge distribution that is derived reveals an unexpected halo of trapped electrons surrounding the ion beam. A charge fluid theory of the effect of finite electron temperature on the focusing of neutralized ion beams (Nucl. Fus. 21, 529 (1981)) is applied to the problem of the Cesium beam final focus at the end of the injector. It is shown that the theory's predictions and assumptions are consistent with the experimental data, and that it accounts for the observed ion beam radius of approx. 5 cm, and the electron halo, including the determination of an electron Debye length of approx. 10 cm.

  10. In situ mitigation of subsurface and peripheral focused ion beam damage via simultaneous pulsed laser heating

    DOE PAGES

    Stanford, Michael G.; Lewis, Brett B.; Iberi, Vighter O.; Fowlkes, Jason Davidson; Tan, Shida; Livengood, Rick; Rack, Philip D.

    2016-02-16

    Focused helium and neon ion (He(+)/Ne(+) ) beam processing has recently been used to push resolution limits of direct-write nanoscale synthesis. The ubiquitous insertion of focused He(+) /Ne(+) beams as the next-generation nanofabrication tool-of-choice is currently limited by deleterious subsurface and peripheral damage induced by the energetic ions in the underlying substrate. The in situ mitigation of subsurface damage induced by He(+)/Ne(+) ion exposures in silicon via a synchronized infrared pulsed laser-assisted process is demonstrated. The pulsed laser assist provides highly localized in situ photothermal energy which reduces the implantation and defect concentration by greater than 90%. The laser-assisted exposuremore » process is also shown to reduce peripheral defects in He(+) patterned graphene, which makes this process an attractive candidate for direct-write patterning of 2D materials. In conclusion, these results offer a necessary solution for the applicability of high-resolution direct-write nanoscale material processing via focused ion beams.« less

  11. In Situ Mitigation of Subsurface and Peripheral Focused Ion Beam Damage via Simultaneous Pulsed Laser Heating.

    PubMed

    Stanford, Michael G; Lewis, Brett B; Iberi, Vighter; Fowlkes, Jason D; Tan, Shida; Livengood, Rick; Rack, Philip D

    2016-04-01

    Focused helium and neon ion (He(+)/Ne(+)) beam processing has recently been used to push resolution limits of direct-write nanoscale synthesis. The ubiquitous insertion of focused He(+)/Ne(+) beams as the next-generation nanofabrication tool-of-choice is currently limited by deleterious subsurface and peripheral damage induced by the energetic ions in the underlying substrate. The in situ mitigation of subsurface damage induced by He(+)/Ne(+) ion exposures in silicon via a synchronized infrared pulsed laser-assisted process is demonstrated. The pulsed laser assist provides highly localized in situ photothermal energy which reduces the implantation and defect concentration by greater than 90%. The laser-assisted exposure process is also shown to reduce peripheral defects in He(+) patterned graphene, which makes this process an attractive candidate for direct-write patterning of 2D materials. These results offer a necessary solution for the applicability of high-resolution direct-write nanoscale material processing via focused ion beams. PMID:26864147

  12. In Situ Mitigation of Subsurface and Peripheral Focused Ion Beam Damage via Simultaneous Pulsed Laser Heating.

    PubMed

    Stanford, Michael G; Lewis, Brett B; Iberi, Vighter; Fowlkes, Jason D; Tan, Shida; Livengood, Rick; Rack, Philip D

    2016-04-01

    Focused helium and neon ion (He(+)/Ne(+)) beam processing has recently been used to push resolution limits of direct-write nanoscale synthesis. The ubiquitous insertion of focused He(+)/Ne(+) beams as the next-generation nanofabrication tool-of-choice is currently limited by deleterious subsurface and peripheral damage induced by the energetic ions in the underlying substrate. The in situ mitigation of subsurface damage induced by He(+)/Ne(+) ion exposures in silicon via a synchronized infrared pulsed laser-assisted process is demonstrated. The pulsed laser assist provides highly localized in situ photothermal energy which reduces the implantation and defect concentration by greater than 90%. The laser-assisted exposure process is also shown to reduce peripheral defects in He(+) patterned graphene, which makes this process an attractive candidate for direct-write patterning of 2D materials. These results offer a necessary solution for the applicability of high-resolution direct-write nanoscale material processing via focused ion beams.

  13. Variable-spot ion beam figuring

    NASA Astrophysics Data System (ADS)

    Wu, Lixiang; Qiu, Keqiang; Fu, Shaojun

    2016-03-01

    This paper introduces a new scheme of ion beam figuring (IBF), or rather variable-spot IBF, which is conducted at a constant scanning velocity with variable-spot ion beam collimated by a variable diaphragm. It aims at improving the reachability and adaptation of the figuring process within the limits of machine dynamics by varying the ion beam spot size instead of the scanning velocity. In contrast to the dwell time algorithm in the conventional IBF, the variable-spot IBF adopts a new algorithm, which consists of the scan path programming and the trajectory optimization using pattern search. In this algorithm, instead of the dwell time, a new concept, integral etching time, is proposed to interpret the process of variable-spot IBF. We conducted simulations to verify its feasibility and practicality. The simulation results indicate the variable-spot IBF is a promising alternative to the conventional approach.

  14. Pseudo ribbon metal ion beam source

    SciTech Connect

    Stepanov, Igor B. Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

    2014-02-15

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

  15. Confined ion beam sputtering device and method

    DOEpatents

    Sharp, Donald J.

    1988-01-01

    A hollow cylindrical target, lined internally with a sputter deposit material and open at both ends, surrounds a substrate on which sputtered deposition is to be obtained. An ion beam received through either one or both ends of the open cylindrical target is forced by a negative bias applied to the target to diverge so that ions impinge at acute angles at different points of the cylindrical target surface. The ion impingement results in a radially inward and downstream directed flux of sputter deposit particles that are received by the substrate. A positive bias applied to the substrate enhances divergence of the approaching ion beams to generate a higher sputtered deposition flux rate. Alternatively, a negative bias applied to the substrate induces the core portion of the ion beams to reach the substrate and provide ion polishing of the sputtered deposit thereon.

  16. Confined ion beam sputtering device and method

    DOEpatents

    Sharp, D.J.

    1986-03-25

    A hollow cylindrical target, lined internally with a sputter deposit material and open at both ends, surrounds a substrate on which sputtered deposition is to be obtained. An ion beam received through either one or both ends of the open cylindrical target is forced by a negative bias applied to the target to diverge so that ions impinge at acute angles at different points of the cylindrical target surface. The ion impingement results in a radially inward and downstream directed flux of sputter deposit particles that are received by the substrate. A positive bias applied to the substrate enhances divergence of the approaching ion beams to generate a higher sputtered deposition flux rate. Alternatively, a negative bias applied to the substrate induces the core portion of the ion beams to reach the substrate and provide ion polishing of the sputtered deposit thereon.

  17. Radiotherapy With Protons And Ion Beams

    SciTech Connect

    Jaekel, Oliver

    2010-04-26

    The use of proton and ion beams has been proposed more than 60 years ago in 1946 by Robert Wilson. In 1955 the first patients were treated with proton beams in Berkeley. Since then radiotherapy with proton and ion beams has constantly been developed at research centers. Within the last decade, however, a considerable number of hospital based facilities came into operation. In this paper an overview over the basic physical and biological properties of proton and ion beams is given. The basic accelerator concepts are outlined and the design of treatment facilities is described. Then the medical physics aspects of the beam delivery, dosimetry and treatment planning are discussed before the clinical concepts are briefly reviewed.

  18. Radiotherapy With Protons And Ion Beams

    NASA Astrophysics Data System (ADS)

    Jäkel, Oliver

    2010-04-01

    The use of proton and ion beams has been proposed more than 60 years ago in 1946 by Robert Wilson. In 1955 the first patients were treated with proton beams in Berkeley. Since then radiotherapy with proton and ion beams has constantly been developed at research centers. Within the last decade, however, a considerable number of hospital based facilities came into operation. In this paper an overview over the basic physical and biological properties of proton and ion beams is given. The basic accelerator concepts are outlined and the design of treatment facilities is described. Then the medical physics aspects of the beam delivery, dosimetry and treatment planning are discussed before the clinical concepts are briefly reviewed.

  19. Ion beam sputtering in electric propulsion facilities

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Patterson, Michael J.

    1991-01-01

    Experiments were undertaken to determine sputter yields of potential ion beam target materials, to assess the impact of charge exchange on beam diagnostics in large facilities, and to examine material erosion and deposition after a 957 hr test of a 5 kW-class ion thruster. The xenon ion sputter yield of flexible graphite was lower than other graphite forms especially at high angles of incidence. Ion beam charge exchange effects were found to hamper beam probe current collection diagnostics even at pressures from 0.7 to 1.7 mPa. Estimates of the xenon ion beam envelope were made and predictions of the thickness of sputter deposited coatings in the facility were compared with measurements.

  20. Ion beam sputtering in electric propulsion facilities

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Patterson, Michael J.

    1991-01-01

    Experiments were undertaken to determine sputter yields of potential ion beam target materials, to assess the impact of charge exchange on beam diagnostics in large facilities, and to examine material erosion and deposition after a 957-hour test of a 5 kW-class ion thruster. The xenon ion sputter yield of flexible graphite was lower than other graphite forms especialy at high angles of incidence. Ion beam charge exchange effects were found to hamper beam probe current collection diagnostics even at pressures from 0.7 to 1.7 mPa. Estimates of the xenon ion beam envelope were made and predictions of the thickness of sputter deposited coatings in the facility were compared with measurements.

  1. Focused Ion beam source method and Apparatus

    SciTech Connect

    Pellin, Michael J.; Lykke, Keith R.; Lill, Thorsten B.

    1998-08-17

    A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.

  2. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Babbush, C. A.; Vankampen, C. L.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.

  3. Focused ion beam source method and apparatus

    DOEpatents

    Pellin, Michael J.; Lykke, Keith R.; Lill, Thorsten B.

    2000-01-01

    A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.

  4. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Van Kampen, C. L.; Babbush, C. A.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic prosthesis fixation, and dental implants.

  5. Ion-beam technology and applications

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.; Robson, R. R.; Sovey, J. S.

    1977-01-01

    Ion propulsion research and development yields a mature technology that is transferable to a wide range of nonpropulsive applications, including terrestrial and space manufacturing. A xenon ion source was used for an investigation into potential ion-beam applications. The results of cathode tests and discharge-chamber experiments are presented. A series of experiments encompassing a wide range of potential applications is discussed. Two types of processes, sputter deposition, and erosion were studied. Some of the potential applications are thin-film Teflon capacitor fabrication, lubrication applications, ion-beam cleaning and polishing, and surface texturing.

  6. The measurement results of carbon ion beam structure extracted by bent crystal from U-70 accelerator

    NASA Astrophysics Data System (ADS)

    Afonin, A. G.; Barnov, E. V.; Britvich, G. I.; Chesnokov, Yu A.; Chirkov, P. N.; Durum, A. A.; Kostin, M. Yu; Maisheev, V. A.; Pitalev, V. I.; Reshetnikov, S. F.; Yanovich, A. A.; Nazhmudinov, R. M.; Kubankin, A. S.; Shchagin, A. V.

    2016-07-01

    The carbon ion +6C beam with energy 25 GeV/nucleon was extracted by bent crystal from the U-70 ring. The bent angle of silicon crystal was 85 mrad. About 2×105 particles for 109 circulated ions in the ring were observed in beam line 4a after bent crystal. Geometrical parameters, time structure and ion beam structure were measured. The ability of the bent monocrystal to extract and generate ion beam with necessary parameters for regular usage in physical experiments is shown in the first time.

  7. Adaptation of ion beam technology to microfabrication of solid state devices and transducers

    NASA Technical Reports Server (NTRS)

    Topich, J. A.

    1978-01-01

    A number of areas were investigated to determine the potential uses of ion beam techniques in the construction of solid state devices and transducers and the packaging of implantable electronics for biomedical applications. The five areas investigated during the past year were: (1) diode-like devices fabricated on textured silicon; (2) a photolithographic technique for patterning ion beam sputtered PVC (polyvinyl chloride); (3) use of sputtered Teflon as a protective coating for implantable pressure sensors; (4) the sputtering of Macor to seal implantable hybrid circuits; and (5) the use of sputtered Teflon to immobilize enzymes.

  8. The role of space charge compensation for ion beam extraction and ion beam transport (invited)

    SciTech Connect

    Spädtke, Peter

    2014-02-15

    Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation.

  9. The role of space charge compensation for ion beam extraction and ion beam transport (invited).

    PubMed

    Spädtke, Peter

    2014-02-01

    Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation.

  10. (abstract) Optical Scattering and Surface Microroughness of Ion Beam Deposited Au and Pt Thin Films

    NASA Technical Reports Server (NTRS)

    Al-Jumaily, Ghanim A.; Raouf, Nasrat A.; Edlou, Samad M.; Simons, John C.

    1994-01-01

    Thin films of gold and platinum have been deposited onto superpolished fused silica substrates using thermal evaporation, ion assisted deposition (IAD), and ion assisted sputtering. The influence of ion beam flux, thin film material, and deposition rate on the films microroughness have been investigated. Short range surface microroughness of the films has been examined using scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Long range surface microroughness has been characterized using an angle resolved optical scatterometer. Results indicate that ion beam deposited coatings have improved microstructure over thermally evaporated films.

  11. Recoil separator ERNA: ion beam specifications

    NASA Astrophysics Data System (ADS)

    Rogalla, D.; Aliotta, M.; Barnes, C. A.; Campajola, L.; D'Onofrio, A.; Fritz, E.; Gialanella, L.; Greife, U.; Imbriani, G.; Ordine, A.; Ossmann, J.; Roca, V.; Rolfs, C.; Romano, M.; Sabbarese, C.; Schürmann, D.; Schümann, F.; Strieder, F.; Theis, S.; Terrasi, F.; Trautvetter, H. P.

    For improved measurements of the key astrophysical reaction 12C(α,γ)16O in inverted kinematics, a recoil separator ERNA is being developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with about 50% efficiency. Calculations of the ion beam optics including all filtering and focusing elements of ERNA are presented. Since the 12C projectiles and the 16O recoils have essentially the same momentum, and since the 12C ion beam emerging from the accelerator passes through a momentum filter (analysing magnet), the 12C ion beam must be as free as possible from 16O contamination for ERNA to succeed. In the present work, the 16O contamination was reduced from a level of 1 × 10-11 to a level below 2 × 10-29 by the installation of Wien filters both before and after the analysing magnet. The measurement of these and other beam specifications involved other parts of the final ERNA layout - sequentially a Wien filter, a 60˚ dipole magnet, another Wien filter, and a ΔE-E telescope. The setup led to a measured suppression factor of 5 × 10-18 for the 12C ion beam. The experiments also indicate that an almost free choice of the charge state for the 16O recoils is possible in the separator.

  12. Heavy ion beams for inertial fusion

    SciTech Connect

    Godlove, T.F.; Herrmannsfeldt, W.B.

    1980-05-01

    The United States' program in inertial confinement fusion (ICF) is described in this paper, with emphasis on the studies of the use of intense high energy beams of heavy ions to provide the power and energy needed to initiate thermonuclear burn. Preliminary calculations of the transport of intense ion beams in an electrostatic quadrupole focussing structure are discussed.

  13. Focused ion beam micromilling and articles therefrom

    DOEpatents

    Lamartine, Bruce C.; Stutz, Roger A.

    1998-01-01

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

  14. Temperature-dependent ion beam mixing

    SciTech Connect

    Rehn, L.E.; Alexander, D.E.

    1993-08-01

    Recent work on enhanced interdiffusion rates during ion-beam mixing at elevated temperatures is reviewed. As discussed previously, expected increase in ion-beam mixing rates due to `radiation-enhanced diffusion` (RED), i.e. the free migration of isolated vacancy and interstitial defects, is well documented in single-crystal specimens in the range of 0.4 to 0.6 of absolute melting temperature. In contrast, the increase often observed at somewhat lower temperatures during ion-beam mixing of polycrystalline specimens is not well understood. However, sufficient evidence is available to show that this increase reflects intracascade enhancement of a thermally-activated process that also occurs without irradiation. Recent evidence is presented which suggests that this process is Diffusion-induced Grain-Boundary Migration (DIGM). An important complementary conclusion is that because ion-beam mixing in single-crystal specimens exhibits no significant temperature dependence below that of RED, models that invoke only irradiation-specific phenomena, e.g., cascade-overlap, thermal-spikes, or liquid-diffusion, and hence which predict no difference in mixing behavior between single- or poly-crystalline specimens, cannot account for the existing results.

  15. Ion Beam Analysis Techniques in Interdisciplinary Applications

    SciTech Connect

    Respaldiza, Miguel A.; Ager, Francisco J.

    1999-12-31

    The ion beam analysis techniques emerge in the last years as one of the main applications of electrostatic accelerators. A short summary of the most used IBA techniques will be given as well as some examples of applications in interdisciplinary sciences.

  16. Ion beam analysis techniques in interdisciplinary applications

    SciTech Connect

    Respaldiza, Miguel A.; Ager, Francisco J.

    1999-11-16

    The ion beam analysis techniques emerge in the last years as one of the main applications of electrostatic accelerators. A short summary of the most used IBA techniques will be given as well as some examples of applications in interdisciplinary sciences.

  17. Upgoing ion beams. I - Microscopic analysis

    NASA Astrophysics Data System (ADS)

    Kaufmann, R. L.; Kintner, P. M.

    1982-12-01

    The stability of electrostatic waves with frequencies near the hydrogen cyclotron frequency is investigated for an auroral plasma containing an ion beam by studying the relationship between low-frequency waves (0-1 kHz) and particles seen by the S3-3 satellite. It is concluded that only electrostatic hydrogen ion cyclotron (EHC) waves can be generated at the observed frequencies by the observed energetic particles, with the waves being produced either by drifting electrons or by the ion beam. In the model developed, ion beams are seen with their observed temperatures because they have evolved to a weakly unstable configuration in which the wave growth length is comparable to the width of the beam region. Waves are well confined to the beams because they are damped rapidly in the adjacent plasma, and the mirror effect can maintain a weak instability over a considerable altitude range. It is proposed that this effect is a source for strong pitch angle scattering, as well as an explanation for the nonexistence of downgoing ion beams.

  18. Radioactive ion beams in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Gialanella, L.

    2016-09-01

    Unstable nuclei play a crucial role in the Universe. In this lecture, after a short introduction to the field of Nuclear Astrophysics, few selected cases in stellar evolution and nucleosynthesis are discussed to illustrate the importance and peculiarities of processes involving unstable species. Finally, some experimental techniques useful for measurements using radioactive ion beams and the perspectives in this field are presented.

  19. Ion beam parameters of a plasma accelerator

    SciTech Connect

    Nazarov, V.G.; Vinogradov, A.M.; Veselovzorov, A.N.; Efremov, V.K.

    1987-08-01

    The aim of this investigation was to determine the dependences of the current density, the energy, and the divergence of the ion beams of an UZDP-type source (a plasma accelerator with closed electron drift in the accelerator channel and an extended zone of ion acceleration) on the parameters which determine its performance, and to establish qualitative relationships between these values.

  20. Focused ion beam micromilling and articles therefrom

    DOEpatents

    Lamartine, B.C.; Stutz, R.A.

    1998-06-30

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

  1. Intense Pulsed Heavy Ion Beam Technology

    NASA Astrophysics Data System (ADS)

    Masugata, Katsumi; Ito, Hiroaki

    Development of intense pulsed heavy ion beam accelerator technology is described for the application of materials processing. Gas puff plasma gun and vacuum arc discharge plasma gun were developed as an active ion source for magnetically insulated pulsed ion diode. Source plasma of nitrogen and aluminum were successfully produced with the gas puff plasma gun and the vacuum arc plasma gun, respectively. The ion diode was successfully operated with gas puff plasma gun at diode voltage 190 kV, diode current 2.2 kA and nitrogen ion beam of ion current density 27 A/cm2 was obtained. The ion composition was evaluated by a Thomson parabola spectrometer and the purity of the nitrogen ion beam was estimated to be 86%. The diode also operated with aluminum ion source of vacuum arc plasma gun. The ion diode was operated at 200 kV, 12 kA, and aluminum ion beam of current density 230 A/cm2 was obtained. The beam consists of aluminum ions (Al(1-3)+) of energy 60-400 keV, and protons (90-130 keV), and the purity was estimated to be 89 %. The development of the bipolar pulse accelerator (BPA) was reported. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. The generator was tested with dummy load of 7.5 ohm, bipolar pulses of -138 kV, 72 ns (1st pulse) and +130 kV, 70 ns (2nd pulse) were succesively generated. By applying the bipolar pulse to the drift tube of the BPA, nitrogen ion beam of 2 A/cm2 was observed in the cathode, which suggests the bipolar pulse acceleration.

  2. Ion beam and plasma jet based methods in ultra-precision optics manufacturing

    NASA Astrophysics Data System (ADS)

    Arnold, Th.; Boehm, G.; Paetzelt, H.; Pietag, F.

    2015-01-01

    Ion beam and plasma jet based techniques can be used in alternative machining processes for generating and finishing of ultra-precision optical surfaces. Since atomistic mechanisms are responsible for surface material modification, etching, and deposition, very high accuracy on the atomic level can be achieved. Various advanced techniques like pulse-width modulated ion beam figuring, sub-aperture reactive ion beam etching, or ion beam assisted structuring, planarization and smoothing technologies have been investigated aiming at precision on sub-nanometer height scale and lateral scales ranging over the full spatial wavelength range from nanometers to meters. Additionally, different atmospheric reactive plasma jet processes and plasma jet assisted process chains for generating, correction and smoothing of complex shaped optical surfaces like aspheres with large departures to best fit sphere or free forms exhibiting strong gradients have been developed in the last decade. In the paper an overview to the most recent trends of non-conventional ultra-precision optics processing is given and latest results of optics manufacturing are shown. Specific examples are given to demonstrate that form generation (e.g. for laser beam shaping optics) and surface finishing and polishing using atmospheric plasma jet tools are promising applications exhibiting advantages with respect to process efficiency and flexibility. Furthermore, the capabilities of ion beam surface figure correction using a new approach to control the tool function are demonstrated.

  3. Replication of the nano-scale mold fabricated with focused ion beam

    NASA Astrophysics Data System (ADS)

    Gao, J. X.; Chan-Park, M. B.; Xie, D. Z.; Ngoi, Bryan K. A.

    2004-12-01

    Silicon mold fabricated with Focused Ion Beam lithography (FIB) was used to make silicone elastomer molds. The silicon mold is composed of lattice of holes which the diameter and depth are about 200 nm and 60 nm, respectively. The silicone elastomer material was then used to replicate slavery mold. Our study show the replication process with the elastomer mold had been performed successfully and the diameter of humps on the elastomer mold is near to that of holes on the master mold. But the height of humps in the elastomer mold is only 42 nm and it is different from the depth of holes in the master mold.

  4. Ion beam sputter etching and deposition of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Sovey, J. S.; Miller, T. B.; Crandall, K. S.

    1978-01-01

    Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanisms and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

  5. Ion beam sputter etching and deposition of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Sovey, J. S.; Miller, T. B.; Crandall, K. S.

    1978-01-01

    Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanism and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

  6. Accessing defect dynamics using intense, nanosecond pulsed ion beams

    SciTech Connect

    Persaud, A.; Barnard, J. J.; Guo, H.; Hosemann, P.; Lidia, S.; Minor, A. M.; Seidl, P. A.; Schenkel, T.

    2015-06-18

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystal Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.

  7. Accessing defect dynamics using intense, nanosecond pulsed ion beams

    DOE PAGES

    Persaud, A.; Barnard, J. J.; Guo, H.; Hosemann, P.; Lidia, S.; Minor, A. M.; Seidl, P. A.; Schenkel, T.

    2015-06-18

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystalmore » Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.« less

  8. Atomic-scale thermocapillary flow in focused ion beam milling

    SciTech Connect

    Das, K.; Johnson, H. T.; Freund, J. B.

    2015-05-15

    Focused ion beams provide a means of nanometer-scale manufacturing and material processing, which is used for applications such as forming nanometer-scale pores in thin films for DNA sequencing. We investigate such a configuration with Ga{sup +} bombardment of a Si thin-film target using molecular dynamics simulation. For a range of ion intensities in a realistic configuration, a recirculating melt region develops, which is seen to flow with a symmetrical pattern, counter to how it would flow were it driven by the ion momentum flux. Such flow is potentially important for the shape and composition of the formed structures. Relevant stress scales and estimated physical properties of silicon under these extreme conditions support the importance thermocapillary effects. A flow model with Marangoni forcing, based upon the temperature gradient and geometry from the atomistic simulation, indeed reproduces the flow and thus could be used to anticipate such flows and their influence in applications.

  9. Laser and focused ion beam combined machining for micro dies.

    PubMed

    Yoshida, Y; Okazaki, W; Uchida, T

    2012-02-01

    We have developed a laser and focused ion beam (FIB) compound process for press mold dies of a micro lens array (MLA) and a micro needle array (MNA) in a glassy carbon (GC). The press mold die of the MLA was roughly fabricated by UV-YAG laser. After this process, we finished this surface by scanning FIB. As a result, higher accuracy and good roughness of surface profile can be realized. An optical glass is used to confirm the shape of lens. Moreover, we fabricated 6 × 6 through-holes in the GC by the spiral drilling in addition to the focus position movement of the UV laser for press mold die of the MNA. After the FIB process, we were able to make the needle die of surface and hole wall roughness less than 0.9 μm. A silicon rubber is used to confirm the shape of the holes.

  10. Formation of cobalt silicide by ion beam mixing

    NASA Astrophysics Data System (ADS)

    Min, Ye; Burte, Edmund P.; Ryssel, Heiner

    1991-07-01

    The formation of cobalt silicides by arsenic ion implantation through a cobalt film which causes a mixing of the metal with the silicon substrate was investigated. Furthermore, cobalt suicides were formed by rapid thermal annealing (RTA). Sheet resistance and silicide phases of implanted Co/Si samples depend on the As dose. Ion beam mixing at doses higher than 5 × 10 15 cm -2 and RTA at temperatures T ⩾ 900° C result in almost equal values of Rs. RBS and XRD spectra of these samples illustrate the formation of a homogeneous CoSi 2 layer. Significant lateral growth of cobalt silicide beyond the edge of patterned SiO 2 was observed in samples which were only subjected to an RTA process ( T ⩾ 900 ° C), while this lateral suicide growth could be reduced efficiently by As implantation prior to RTA.

  11. Laser-cooled continuous ion beams

    SciTech Connect

    Schiffer, J.P.; Hangst, J.S.; Nielsen, J.S.

    1995-08-01

    A collaboration with a group in Arhus, Denmark, using their storage ring ASTRID, brought about better understanding of ion beams cooled to very low temperatures. The longitudinal Schottky fluctuation noise signals from a cooled beam were studied. The fluctuation signals are distorted by the effects of space charge as was observed in earlier measurements at other facilities. However, the signal also exhibits previously unobserved coherent components. The ions` velocity distribution, measured by a laser fluorescence technique suggests that the coherence is due to suppression of Landau damping. The observed behavior has important implications for the eventual attainment of a crystalline ion beam in a storage ring. A significant issue is the transverse temperature of the beam -- where no direct diagnostics are available and where molecular dynamics simulations raise interesting questions about equilibrium.

  12. Scanning He+ Ion Beam Microscopy and Metrology

    SciTech Connect

    Joy, David C.

    2011-11-10

    The CD-SEM has been the tool of choice for the imaging and metrology of semiconductor devices for the past three decades but now, with critical dimensions at the nanometer scale, electron beam instruments can no longer deliver adequate performance. A scanning microscope using a He+ ion beam offers superior resolution and depth of field, and provides enhanced imaging contrast. Device metrology performed using ion beam imaging produces data which is comparable to or better than that from a conventional CD-SEM although there are significant differences in the experimental conditions required and in the details of image formation. The charging generated by a He+ beam, and the sample damage that it can cause, require care in operation but are not major problems.

  13. Rhenium ion beam for implantation into semiconductors

    SciTech Connect

    Kulevoy, T. V.; Seleznev, D. N.; Alyoshin, M. E.; Kraevsky, S. V.; Yakushin, P. E.; Khoroshilov, V. V.; Gerasimenko, N. N.; Smirnov, D. I.; Fedorov, P. A.; Temirov, A. A.

    2012-02-15

    At the ion source test bench in Institute for Theoretical and Experimental Physics the program of ion source development for semiconductor industry is in progress. In framework of the program the Metal Vapor Vacuum Arc ion source for germanium and rhenium ion beam generation was developed and investigated. It was shown that at special conditions of ion beam implantation it is possible to fabricate not only homogenous layers of rhenium silicides solid solutions but also clusters of this compound with properties of quantum dots. At the present moment the compound is very interesting for semiconductor industry, especially for nanoelectronics and nanophotonics, but there is no very developed technology for production of nanostructures (for example quantum sized structures) with required parameters. The results of materials synthesis and exploration are presented.

  14. Surface processing using water cluster ion beams

    NASA Astrophysics Data System (ADS)

    Takaoka, Gikan H.; Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku

    2013-07-01

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO2, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  15. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, J.

    1984-01-01

    The application of the ion beam technique to the nitriding of steels is described. It is indicated that the technique can be successfully applied to nitriding. Some of the structural changes obtained by this technique are similar to those obtained by ion nitriding. The main difference is the absence of the iron nitride diffraction lines. It is found that the dependence of the resultant microhardness on beam voltage for super nitralloy is different from that of 304 stainless steel.

  16. Mechanism of ion-beam-induced deposition

    SciTech Connect

    Dubner, A.D.

    1990-01-01

    Ion-beam induced deposition (IBID) is described as well as the system developed for in-situ measurement of IBID. Gold films were deposited on quartz crystal microbalances (QCM) by decomposing C{sub 7}H{sub 7}F{sub 6}O{sub 2}Au (dimethyl gold hexafluoroacetylacetonate, or DMG (hfac)) with 2- to 10-keV Xe{sup +}, Kr{sup +}, Ar{sup +}, Ne{sup +}, or He{sup +} ion beams. A conceptual model for ion beam induced deposition is presented which relates the net deposition yield to the gas adsorption, the decomposition cross section, and the sputter yield. To test this model, the deposition rate with 5-keV Ar{sup +} ions was measured in-situ as a function of ion current, gas pressure, and substrate temperature using the QCM. The deposition yield (mass deposited per incident ion) increased with increasing gas pressure and decreasing substrate temperature. The QCM was also used to measure the adsorption of DMG (hfac). Results demonstrate that the variation in deposition yield with temperature and pressure was proportional to the number of DMG (hfac) molecules adsorbed per cm{sup 2}, and verify the conceptual model. Based on the observed correlation between deposition yield and adsorption, a decomposition cross section for 5-keV argon ions of 2 {times} 10{sup {minus}13} cm{sup 2} was estimated.

  17. Radioactive Ion Beam Production Capabilities at the Holifield Radioactive Ion Beam Facility

    SciTech Connect

    Beene, James R; Dowling, Darryl T; Gross, Carl J; Juras, Raymond C; Liu, Yuan; Meigs, Martha J; Mendez, II, Anthony J; Nazarewicz, Witold; Sinclair, John William; Stracener, Daniel W; Tatum, B Alan

    2011-01-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of HRIBF is the production of high-quality beams of short-lived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions.

  18. High current ion beam transport using solenoids

    SciTech Connect

    Hollinger, R.; Spaedtke, P.

    2008-02-15

    In the framework of the future project FAIR several upgrade programs and construction of new facilities are in progress such as the U{sup 4+} upgrade for the existing high current injector and the new 70 MeV proton injector. For both injectors solenoids in the low energy beam transport section are foreseen to inject the beam into the following rf accelerator. The paper presents beam quality measurements of high current ion beams behind a solenoid using a slit-grid emittance measurement device, viewing targets, and a pepper pot measurement device at the high current test bench at GSI.

  19. Spectrometer for cluster ion beam induced luminescence

    SciTech Connect

    Ryuto, H. Sakata, A.; Takeuchi, M.; Takaoka, G. H.; Musumeci, F.

    2015-02-15

    A spectrometer to detect the ultra-weak luminescence originated by the collision of cluster ions on the surfaces of solid materials was constructed. This spectrometer consists of 11 photomultipliers with band-pass interference filters that can detect the luminescence within the wavelength ranging from 300 to 700 nm and of a photomultiplier without filter. The calibration of the detection system was performed using the photons emitted from a strontium aluminate fluorescent tape and from a high temperature tungsten filament. Preliminary measurements show the ability of this spectrometer to detect the cluster ion beam induced luminescence.

  20. Plasma formed ion beam projection lithography system

    DOEpatents

    Leung, Ka-Ngo; Lee, Yung-Hee Yvette; Ngo, Vinh; Zahir, Nastaran

    2002-01-01

    A plasma-formed ion-beam projection lithography (IPL) system eliminates the acceleration stage between the ion source and stencil mask of a conventional IPL system. Instead a much thicker mask is used as a beam forming or extraction electrode, positioned next to the plasma in the ion source. Thus the entire beam forming electrode or mask is illuminated uniformly with the source plasma. The extracted beam passes through an acceleration and reduction stage onto the resist coated wafer. Low energy ions, about 30 eV, pass through the mask, minimizing heating, scattering, and sputtering.

  1. Physics with fast molecular-ion beams

    SciTech Connect

    Kanter, E.P.

    1980-01-01

    Fast (MeV) molecular-ion beams provide a unique source of energetic projectile nuclei which are correlated in space and time. The recognition of this property has prompted several recent investigations of various aspects of the interactions of these ions with matter. High-resolution measurements on the fragments resulting from these interactions have already yielded a wealth of new information on such diverse topics as plasma oscillations in solids and stereochemical structures of molecular ions as well as a variety of atomic collision phenomena. The general features of several such experiments will be discussed and recent results will be presented.

  2. Graphene engineering by neon ion beams

    DOE PAGES

    Iberi, Vighter; Ievlev, Anton V.; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V.; Joy, David C.; Rondinone, Adam J.; Belianinov, Alex; Ovchinnikova, Olga S.

    2016-02-18

    Achieving the ultimate limits of materials and device performance necessitates the engineering of matter with atomic, molecular, and mesoscale fidelity. While common for organic and macromolecular chemistry, these capabilities are virtually absent for 2D materials. In contrast to the undesired effect of ion implantation from focused ion beam (FIB) lithography with gallium ions, and proximity effects in standard e-beam lithography techniques, the shorter mean free path and interaction volumes of helium and neon ions offer a new route for clean, resist free nanofabrication. Furthermore, with the advent of scanning helium ion microscopy, maskless He+ and Ne+ beam lithography of graphenemore » based nanoelectronics is coming to the forefront. Here, we will discuss the use of energetic Ne ions in engineering graphene devices and explore the mechanical, electromechanical and chemical properties of the ion-milled devices using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we demonstrate that the mechanical, electrical and optical properties of the exact same devices can be quantitatively extracted. Additionally, the effect of defects inherent in ion beam direct-write lithography, on the overall performance of the fabricated devices is elucidated.« less

  3. Ion beam deposition in materials research

    NASA Astrophysics Data System (ADS)

    Zuhr, R. A.; Pennycook, S. J.; Noggle, T. S.; Herbots, N.; Haynes, T. E.; Appleton, B. R.

    1989-02-01

    Ion beam deposition (IBD) is the direct formation of thin films using a low-energy (tens of eV) mass-analyzed ion beam. The process allows depositions in which the energy, isotopic species, deposition rate, defect production, and many other beam and sample parameters can be accurately controlled. This paper will review recent research at ORNL on the IBD process and the effects of deposition parameters on the materials properties of deposited thin films, epitaxial layers, and isotopic heterostructures. A variety of techniques including ion scattering/channeling, cross-sectional transmission electron microscopy, scanning electron microscopy, and Auger spectroscopy has been used for analysis. The fabrication of isotopic heterostructures of 74Ge and 30Si will be discussed, as well as the fabrication of metal and semiconductor overlayers on Si and Ge. The use of IBD for low-temperature epitaxy of 30Si on Si and 76Ge on Ge will be presented. The use of self-ion sputter cleaning and in situ reactive ion cleaning as methods for preparing single-crystal substrates for epitaxial deposition will be discussed. Examples of IBD formation of oxides and suicides on Si at low temperatures will also be presented.

  4. Holifield Radioactive Ion Beam Facility Status

    SciTech Connect

    Stracener, Daniel W; Beene, James R; Dowling, Darryl T; Juras, Raymond C; Liu, Yuan; Meigs, Martha J; Mendez, II, Anthony J; Mueller, Paul Edward; Sinclair, John William; Tatum, B Alan; Sinclair IV, John W

    2009-01-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL) produces high-quality beams of short-lived radioactive isotopes for nuclear science research, and is currently unique worldwide in the ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier. HRIBF is undergoing a multi-phase upgrade. Phase I (completed 2005) was construction of the High Power Target Laboratory to provide the on-going Isotope Separator On-Line (ISOL) development program with a venue for testing new targets, ion sources, and radioactive ion beam (RIB) production techniques with high-power beams. Phase II, which is on schedule for completion in September 2009, is the Injector for Radioactive Ion Species 2 (IRIS2), a second RIB production station that will improve facility reliability and accommodate new ion sources, new RIB production targets, and some innovative RIB purification techniques, including laser applications. The Phase III goal is to substantially improve facility performance by replacing or supplementing the Oak Ridge Isochronous Cyclotron (ORIC) production accelerator with either a high-power 25-50 MeV electron accelerator or a high-current multi-beam commercial cyclotron. Either upgrade is applicable to R&D on isotope production for medical or other applications.

  5. Time resolved ion beam induced charge collection

    SciTech Connect

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

    2000-04-01

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

  6. Multiple Electron Stripping of Heavy Ion Beams

    SciTech Connect

    D. Mueller; L. Grisham; I. Kaganovich; R. L. Watson; V. Horvat; K. E. Zaharakis; Y. Peng

    2002-06-25

    One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 Mev/amu with charge state 1 currently do not exist. Hence, the stripping cross-sections used to model the performance of heavy ion fusion driver beams have, up to now, been based upon theoretical calculations. We have investigated experimentally the stripping of 3.4 Mev/amu Kr 7+ and Xe +11 in N2; 10.2 MeV/amu Ar +6 in He, N2, Ar and Xe; 19 MeV/amu Ar +8 in He, N2, Ar and Xe; 30 MeV He 1 + in He, N2, Ar and Xe; and 38 MeV/amu N +6 in He, N2, Ar and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

  7. Solenoid Transport of an Intense Ion Beam

    NASA Astrophysics Data System (ADS)

    Coleman, J. E.; Henestroza, E.; Roy, P. K.; Waldron, W. L.; Armijo, J.; Baca, D.; Seidl, P. A.; Haber, I.; Sharp, W. M.; Vay, J. L.; Welch, D. R.

    2006-10-01

    Future WDM and HEDP experiments may use solenoids for transverse focusing of low energy, space-charge dominated ion beams during acceleration. An experiment to transport a 10 μs long, singly charged potassium ion bunch at an ion energy of 0.3 MeV and current of 45 mA through a solenoid lattice (STX) has been commissioned at LBNL. The beam should establish a Brillouin-flow condition, particle rotation at the Larmor frequency, with fields greater than 2T. The principal objectives of the STX are to match and transport the space-charge dominated ion beam and to study mechanisms that would degrade beam quality such as focusing-field aberrations, beam halo, spacing of lattice elements, and electron-cloud and gas effects. A qualitative comparison of experimental and calculated results are presented, which include time resolved transverse phase-space of the beam at different diagnostic planes throughout the focusing lattice, beam current density and beam-induced gas desorption, ionization and electron effects. (This work was supported by the U.S. D.O.E. under DE-AC02-05H11231)

  8. Target Development for Radioactive Ion Beam Generation

    NASA Astrophysics Data System (ADS)

    Kronenberg, A.; Carter, H. K.; Stracener, D. W.; Bilheux, J. C.; Cizewski, J. A.; Koester, U.

    2004-10-01

    Development of ion beams of short-lived isotopes is crucial for modern nuclear structure and nuclear astrophysics. For example, ^82Ge,^130+xSn, ^92,94,95Sr beams are of interest but impurities and low intensities have prevented them from being useful. The code HSC-5 [1], with an extensive thermochemical database, predicts which chemical compounds may be transported within the target-ion source. The code also allows us to predict stability of target materials as function of temperature and pressure. So, a number of new targets have been fabricated and tested for use at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory, based on the ISOL technique. Recent results from off-line and on-line tests at HRIBF and CERN-ISOLDE will be presented. This research was sponsored by the NNSA under Stewardship Science Academic Alliance program through DOE Cooperative Agreement # DE-FC03-3NA00143. [1] HSC Chemistry for Windows - Chemical Reaction and Equilibrium Software with extensive Thermochemical Database, Outokumpu Research Oy, Pori, Finnland

  9. Target Development for Radioactive Ion Beam Generation

    NASA Astrophysics Data System (ADS)

    Kronenberg, A.; Carter, H. K.; Stracener, D.; Bilheux, J.; Cizewski, J. A.; Koester, U.

    2004-11-01

    Development of ion beams of short-lived isotopes is crucial for modern nuclear structure and nuclear astrophysics. For example, ^82Ge, ^130+xSn, ^92,94,95Sr beams are of interest but impurities and low intensities have prevented them from being useful. The code HSC-5 [1], with an extensive thermochemical database predicts which chemical compounds may be transported within the target-ion source. The code also allows us to predict stability of target materials as function of temperature and pressure. So, a number of new targets have been fabricated and tested for use at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory, based on the ISOL technique. Recent results from off-line and on-line tests at HRIBF and CERN-ISOLDE will be presented. This research was sponsored by the NNSA under Stewardship Science Academic Alliance program through DOE Cooperative Agreement # DE-FC03-3NA00143. [1] HSC Chemistry for Windows Chemical Reaction and Equilibrium Software with extensive Thermochemical Database, Outokumpu Research Oy, Pori, Finnland

  10. Post-acceleration of laser-induced ion beams

    NASA Astrophysics Data System (ADS)

    Nassisi, V.; Delle Side, D.

    2015-04-01

    A complete review of the essential and recent developments in the field of post-acceleration of laser-induced ion beams is presented. After a brief introduction to the physics of low-intensity nanosecond laser-matter interaction, the details of ions extraction and acceleration are critically analyzed and the key parameters to obtain good-quality ion beams are illustrated. A description of the most common ion beam diagnosis system is given, together with the associated analytical techniques.

  11. Persistent ion beam induced conductivity in zinc oxide nanowires

    SciTech Connect

    Johannes, Andreas; Niepelt, Raphael; Gnauck, Martin; Ronning, Carsten

    2011-12-19

    We report persistently increased conduction in ZnO nanowires irradiated by ion beam with various ion energies and species. This effect is shown to be related to the already known persistent photo conduction in ZnO and dubbed persistent ion beam induced conduction. Both effects show similar excitation efficiency, decay rates, and chemical sensitivity. Persistent ion beam induced conduction will potentially allow countable (i.e., single dopant) implantation in ZnO nanostructures and other materials showing persistent photo conduction.

  12. High sensitivity charge amplifier for ion beam uniformity monitor

    DOEpatents

    Johnson, Gary W.

    2001-01-01

    An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

  13. Performance and Controllability of Pulsed Ion Beam Ablation Propulsion

    SciTech Connect

    Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi

    2006-05-02

    We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

  14. Spacecraft charging during ion beam emissions in sunlight

    NASA Technical Reports Server (NTRS)

    Lai, S. T.; Mcneil, W. J.; Aggson, T. L.

    1990-01-01

    During ion beam emissions from the SCATHA satellite, the potential of the negatively charged satellite body shows a sinusoidal oscillation frequency of once-per-spin of the satellite. The minimum occurs when the ion beam is sunward. The processes that may be responsible for the voltage modulation are considered. Neutralization of ion beam space charge by photoelectrons is examined. The photoelectrons are accelerated by the negative potential of the satellite. Effects of electron impact ionization, excitation of metastable states, and photoionization of xenon neutral atoms in the ion beam are studied in detail. Critical ionization velocity interaction is unlikely under the condition considered.

  15. Formation of Mosaic Silicon Oxide Structure during Metal-Assisted Electrochemical Etching of Silicon at High Current Density

    NASA Astrophysics Data System (ADS)

    Cao, Dao Tran; Anh, Cao Tuan; Ngan, Luong Truc Quynh

    2016-05-01

    We have used constant-current, metal-assisted electrochemical etching of silicon in HF/H2O2/ethanol electrolyte to fabricate porous silicon. We found that, at large enough current density, the sponge-like porous silicon structure is replaced by a mosaic structure, which includes islands of various shapes emerging between trenches that have been etched downward. Energy-dispersive x-ray analysis showed that the surface of the mosaic pieces was covered with silicon oxide, while little silicon oxide developed on the surface of trenches. We suggest that the appearance of the mosaic structure can be explained by the increase in the oxidation rate of silicon when the anodic current density increases, combined with no change in the dissolution rate of silicon oxide into the solution. Consequently, above a certain value of anodic current density, there is sufficient residual silicon oxide on the etched surface to create a continuous thin film. However, if the silicon oxide layer is too thick (e.g., due to too high anodic current density or too long etching time), it will become cracked (formation of mosaic pieces), likely due to differences in thermal expansion coefficient between the amorphous silicon oxide layer and crystalline silicon substrate. The oxide is cracked at locations with many defects, and the cracks reveal the silicon substrate. Therefore, at the locations where cracks occur, etching will go sideways and downward, creating trenches.

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

    NASA Astrophysics Data System (ADS)

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

    2009-08-01

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

  17. Ion beam sputter deposited diamond like films

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Rutledge, S. K.

    1982-01-01

    A single argon ion beam source was used to sputter deposit carbon films on fused silica, copper, and tantalum substrates under conditions of sputter deposition alone and sputter deposition combined with simultaneous argon ion bombardment. Simultaneously deposited and ion bombarded carbon films were prepared under conditions of carbon atom removal to arrival ratios of 0, 0.036, and 0.71. Deposition and etch rates were measured for films on fused silica substrates. Resulting characteristics of the deposited films are: electrical resistivity of densities of 2.1 gm/cu cm for sputter deposited films and 2.2 gm/cu cm for simultaneously sputter deposited and Ar ion bombarded films. For films approximately 1700 A thick deposited by either process and at 5550 A wavelength light the reflectance was 0.2, the absorptance was 0.7, the absorption coefficient was 67,000 cm to the -1 and the transmittance was 0.1.

  18. Focused ion beam in dental research.

    PubMed

    Ngo, H; Cairney, J; Munroe, P; Vargas, M; Mount, G

    2000-11-01

    Focused ion beam (FIB) has been available for over 10 yrs but until recently its usage has been confined to the semiconductor industry. It has been developed as an important tool in defect analysis, circuit modification and recently transmission electron microscope sample preparation. This paper introduces FIB and demonstrates its application in dental research. Its ion and electron imaging modes complement the SEM while its ability to prepare TEM samples from a wide range of material will allow the study of new types of adhesive interface. As an example, its use is described in the characterization of the interface of resin to a tribochemically treated surface of an experimental fiber-reinforced resin-based composite. As with all new techniques, the initial learning curve was difficult to manage. This new instrument offers opportunities to expand research in dental materials to areas not possible before.

  19. Dispensing targets for ion beam particle generators

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1974-01-01

    A target for dispensing high energy protons or neutrons or ionized atoms or ionized molecules is provided which comprises a container for the target gas, which is at atmospheric or higher pressure. The container material can release the target gas in the spot where the container is heated above a predetermined temperature by the impact of an ion beam where protons or neutrons are desired, or by electrons where ionized atoms or molecules are desired. On the outside of the container, except for the region where the beam is to impact, there is deposited a layer of a metal which is imperious to gaseous diffusion. A further protective coating of a material is placed over the layer of metal, except at the region of the ion impact area in order to adsorb any unreacted gas in the vacuum in which the target is placed, to thereby prevent reduction of the high vacuum, as well as contamination of the interior of the vacuum chamber.

  20. Magnetically scanned ion beams for radiation therapy

    SciTech Connect

    Alonso, J.R.

    1988-10-01

    The advantageous physical characteristics of slowing-down and stopping charged particle ion beams have been demonstrated to be highly desirable for application to radiation therapy. Specifically, the prospect of concentrating the dose delivered into a sharp-defined treatment volume while keeping to a minimum the total dose to tissues outside this volume is most appealing, offering very significant improvements over what is possible with established radiation therapy techniques. Key to achieving this physical dose distribution in an actual treatment setting is the technique used for delivering the beam into the patient. Magnetically scanned beams are emerging as the technique of choice, but daunting problems remain still in achieving the utmost theoretically possible dose distributions. 21 refs., 2 figs.

  1. Ion Beam Sputtered Coatings of Bioglass

    NASA Technical Reports Server (NTRS)

    Hench, Larry L.; Wilson, J.; Ruzakowski, Patricia Henrietta Anne

    1982-01-01

    The ion beam sputtering technique available at the NASA-Lewis was used to apply coatings of bioglass to ceramic, metallic, and polymeric substrates. Experiments in vivo and in vitro described investigate these coatings. Some degree of substrate masking was obtained in all samples although stability and reactivity equivalent to bulk bioglass was not observed in all coated samples. Some degree of stability was seen in all coated samples that were reacted in vitro. Both metallic and ceramic substrates coated in this manner failed to show significantly improved coatings over those obtained with existing techniques. Implantation of the coated ceramic substrate samples in bone gave no definite bonding as seen with bulk glass; however, partial and patchy bonding was seen. Polymeric substrates in these studies showed promise of success. The coatings applied were sufficient to mask the underlying reactive test surface and tissue adhesion of collagen to bioglass was seen. Hydrophilic, hydrophobic, charged, and uncharged polymeric surfaces were successfully coated.

  2. High efficiency ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G.

    1981-01-01

    An ion accelerator system that successfully combines geometrical and electrostatic focusing principles is presented. This accelerator system uses thin, concave, multiple-hole, closely spaced graphite screen and focusing grids which are coupled to single slot accelerator and decelerator grids to provide high ion extraction efficiency and good focusing. Tests with the system showed a substantial improvement in ion beam current density and collimation as compared with a Pierce electrode configuration. Durability of the thin graphite screen and focusing grids has been proven, and tests are being performed to determine the minimum screen and focusing grid spacing and thickness required to extract the maximum reliable beam current density. Compared with present neutral beam injector accelerator systems, this one has more efficient ion extraction, easier grid alignment, easier fabrication, a less cumbersome design, and the capacity to be constructed in a modular fashion. Conceptual neutral beam injector designs using this modular approach have electrostatic beam deflection plates downstream of each module.

  3. Kinetic Simulations of Ion Beam Neutralization

    SciTech Connect

    Chang, O.; Wang, J.

    2011-05-20

    Full particle PIC simulations are performed to study the neutralization of an ion beam in the cohesionless, mesothermal regime. Simulations further confirmed that neutralization is achieved through interactions between the trapped electrons and the potential well established by the propagation of the beam front along the beam direction and is not through plasma instabilities as previous studies suggested. In the transverse direction, the process is similar to that of the expansion of mesothermal plasma into vacuum. Parametric simulations are also performed to investigate the effects of beam radius and domain boundary condition on the neutralization process. The results suggests that, while the qualitative behavior may be similar in ground tests, quantitative parameters such as the beam potential will be affected significantly by the vacuum chamber because of the limits imposed on the expansion process by the finite chamber space.

  4. Image-projection ion-beam lithography

    SciTech Connect

    Miller, P.A. )

    1989-09-01

    Image-projection ion-beam lithography is an attractive alternative for submicron patterning because it may provide high throughput; it uses demagnification to gain advantages in reticle fabrication, inspection, and lifetime; and it enjoys the precise deposition characteristics of ions which cause essentially no collateral damage. This lithographic option involves extracting low-mass ions (e.g., He{sup +} ) from a plasma source, transmitting the ions at low voltage through a stencil reticle, and then accelerating and focusing the ions electrostatically onto a resist-coated wafer. While the advantages of this technology have been demonstrated experimentally by the work of IMS (Austria), many difficulties still impede extension of the technology to the high-volume production of microelectronic devices. We report a computational study of a lithography system designed to address problem areas in field size, telecentricity, and chromatic and geometric aberration. We present a novel ion-column-design approach and conceptual ion-source and column designs which address these issues. We find that image-projection ion-beam technology should in principle meet high-volume-production requirements. The technical success of our present relatively compact-column design requires that a glow-discharge-based ion source (or equivalent cold source) be developed and that moderate further improvement in geometric aberration levels be obtained. Our system requires that image predistortion be employed during reticle fabrication to overcome distortion due to residual image nonlinearity and space-charge forces. This constitutes a software data preparation step, as do correcting for distortions in electron lithography columns and performing proximity-effect corrections. Areas needing further fundamental work are identified.

  5. Purification of Radioactive Ion Beams by Photodetachment in a RF Quadrupole Ion Beam Cooler

    SciTech Connect

    Liu, Yuan; Beene, James R; Havener, Charles C; Galindo-Uribarri, Alfredo {nmn}; Lewis, Thomas L.

    2009-01-01

    A highly efficient method for suppressing isobar contaminants in negative radioactive ion beams by photodetachment is demonstrated. A laser beam having the appropriate photon energy is used to selectively neutralize the contaminants. The efficiency of photodetachment can be substantially improved when the laser-ion interaction takes place inside a radio frequency quadrupole ion cooler. In off-line experiments with ion beams of stable isotopes, more than 99.9% suppression of Co{sup -}, S{sup -}, and O{sup -} ions has been demonstrated while under the identical conditions only 22% reduction in Ni{sup -} and no reduction in Cl{sup -} and F{sup -} ions were observed. This technique is being developed for on-line purification of a number of interesting radioactive beams, such as {sup 56}Ni, {sup 17,18}F, and {sup 33,36}Cl.

  6. Simulation of ion beam transport through the 400 Kv ion implanter at Michigan Ion Beam Laboratory

    NASA Astrophysics Data System (ADS)

    Naab, F. U.; Toader, O. F.; Was, G. S.

    2013-04-01

    The Michigan Ion Beam Laboratory houses a 400 kV ion implanter. An application that simulates the ion beam trajectories through the implanter from the ion source to the target was developed using the SIMION® code. The goals were to have a tool to develop an intuitive understanding of abstract physics phenomena and diagnose ion trajectories. Using this application, new implanter users of different fields in science quickly understand how the machine works and quickly learn to operate it. In this article we describe the implanter simulation application and compare the parameters of the implanter components obtained from the simulations with the measured ones. The overall agreement between the simulated and measured values of magnetic fields and electric potentials is ˜10%.

  7. Mapping of ion beam induced current changes in FinFETs

    SciTech Connect

    Weis, C. D.; Schuh, A.; Batra, A.; Persaud, A.; Rangelow, I. W.; Bokor, J.; Lo, C. C.; Cabrini, S.; Olynick, D.; Duhey, S.; Schenkel, T.

    2008-09-30

    We report on progress in ion placement into silicon devices with scanning probealignment. The device is imaged with a scanning force microscope (SFM) and an aligned argon beam (20 keV, 36 keV) is scanned over the transistor surface. Holes in the lever of the SFM tip collimate the argon beam to sizes of 1.6 mu m and 100 nm in diameter. Ion impacts upset the channel current due to formation of positive charges in the oxide areas. The induced changes in the source-drain current are recorded in dependence of the ion beam position in respect to the FinFET. Maps of local areas responding to the ion beam are obtained.

  8. Development of a focused ion beam micromachining system

    SciTech Connect

    Pellerin, J.G.; Griffis, D.; Russell, P.E.

    1988-12-01

    Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

  9. Funnel cone for focusing intense ion beams on a target

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Ni, P.

    2009-10-05

    We describe a funnel cone for concentrating an ion beam on a target. The cone utilizes the reflection characteristic of ion beams on solid walls to focus the incident beam andincrease beam intensity on target. The cone has been modeled with the TRIM code. A prototype has been tested and installed for use in the 350-keV K+ NDCX target chamber.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  11. Overview of the LIBRA light ion beam fusion conceptual design

    SciTech Connect

    Moses, G.A.; Kulcinski, G.L.; Bruggink, D.; Engelstad, R.; Lovell, E.; MacFarlane, J.; Musicki, Z.; Peterson, R.; Sawan, M.; Sviatoslavsky, I.

    1989-03-01

    The LIBRA light ion beam fusion commercial reactor study is a self-consistent conceptual design of a 330 MWe power plant with an accompanying economic analysis. Fusion targets are imploded by 4 MJ shaped pulses of 30 MeV Li ions at a rate of 3 Hz. The target gain is 80, leading to a yield of 320 MJ. The high intensity part of the ion plate is delivered by 16 diodes through 16 separate z-pinch plasma channels formed in 100 torr of helium with trace amounts of lithium. The blanket is an array of porous flexible silicon carbide tubes with Li/sub 17/Pb/sub 83/ flowing downward through them. These tubes (INPORT units) shield the target chamber wall from both neutron damage and the shock overpressure of the target explosion. The target chamber is self-pumped by the target explosion generated overpressure into a surge tank partially filled with Li/sub 17/Pb/sub 83/ that surrounds the target chamber. This scheme refreshes the chamber at the desired 3 Hz frequency without excessive pumping demands. The blanket multiplication is 1.2 and the tritium breeding ratio is 1.4. The direct capital cost of LIBRA is estimated to be $2200/kWe.

  12. A gas jet target for radioactive ion beam experiments

    SciTech Connect

    Chipps, K. A.; Greife, U.; Hager, U.; Sarazin, F.; Bardayan, D. W.; Pain, S. D.; Schmitt, K. T.; Smith, M. S.; Blackmon, J. C.; Linhardt, L. E.; Browne, J.; Kontos, A.; Meisel, Z.; Montes, F.; Schatz, H.; Erikson, L. E.; Lemut, A.; and others

    2013-04-19

    New radioactive ion beam (RIB) facilities, like FRIB in the US or FAIR in Europe, will push further away from stability and enable the next generation of nuclear physics experiments. Thus, the need for improved RIB targets is more crucial than ever: developments in exotic beams should coincide with developments in targets for use with those beams, in order for nuclear physics to remain on the cutting edge. Of great importance to the future of RIB physics are scattering, transfer and capture reaction measurements of rare, exotic, and unstable nuclei on light targets such as hydrogen and helium. These measurements require targets that are dense, highly localized, and pure, and conventional targets often suffer too many drawbacks to allow for such experimental designs. Targets must also accommodate the use of large area, highly-segmented silicon detector arrays, high-efficiency gamma arrays, and novel heavy ion detectors to efficiently measure the reaction products. To address this issue, the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) Collaboration led by the Colorado School of Mines (CSM) is in the process of designing, building and testing a supersonic gas jet target for use at existing and future RIB facilities. The gas jet target provides a high density and high purity of target nuclei within a tightly confined region, without the use of windows or backing materials. The design also enables the use of multiple state-of-the-art detection systems.

  13. Atomic force microscope cantilever calibration using a focused ion beam.

    PubMed

    Slattery, Ashley D; Quinton, Jamie S; Gibson, Christopher T

    2012-07-20

    A calibration method is presented for determining the spring constant of atomic force microscope (AFM) cantilevers, which is a modification of the established Cleveland added mass technique. A focused ion beam (FIB) is used to remove a well-defined volume from a cantilever with known density, substantially reducing the uncertainty usually present in the added mass method. The technique can be applied to any type of AFM cantilever; but for the lowest uncertainty it is best applied to silicon cantilevers with spring constants above 0.7 N m(-1), where uncertainty is demonstrated to be typically between 7 and 10%. Despite the removal of mass from the cantilever, the calibration method presented does not impair the probes' ability to acquire data. The technique has been extensively tested in order to verify the underlying assumptions in the method. This method was compared to a number of other calibration methods and practical improvements to some of these techniques were developed, as well as important insights into the behavior of FIB modified cantilevers. These results will prove useful to research groups concerned with the application of microcantilevers to nanoscience, in particular for cases where maintaining pristine AFM tip condition is critical.

  14. Dual ion beam deposition of carbon films with diamondlike properties

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Swec, D. M.; Angus, J. C.

    1984-01-01

    A single and dual ion beam system was used to generate amorphous carbon films with diamond like properties. A methane/argon mixture at a molar ratio of 0.28 was ionized in the low pressure discharge chamber of a 30-cm-diameter ion source. A second ion source, 8 cm in diameter was used to direct a beam of 600 eV Argon ions on the substrates (fused silica or silicon) while the deposition from the 30-cm ion source was taking place. Nuclear reaction and combustion analysis indicate H/C ratios for the films to be 1.00. This high value of H/C, it is felt, allowed the films to have good transmittance. The films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Although the measured density of the films was approximately 1.8 gm/cu cm, a value lower than diamond, the films exhibited other properties that were relatively close to diamond. These films were compared with diamondlike films generated by sputtering a graphite target.

  15. Current density compression of intense ion beams

    NASA Astrophysics Data System (ADS)

    Sefkow, Adam Bennett

    Current density compression of intense ion beams in space and time is required for heavy ion fusion, in order to achieve the necessary intensities to implode an inertial confinement fusion target. Longitudinal compression to high current in a short pulse is achieved by imposing a velocity tilt upon the space-charge-dominated charge bunch, and a variety of means exist for simultaneous transverse focusing to a coincident focal plane. Compression to the desired levels requires sufficient neutralization of the beam by a pre-formed plasma during final transport. The physics of current density compression is studied in scaled experiments relevant for the operating regime of a heavy ion driver, and related theory and advanced particle-in-cell simulations provide valuable insight into the physical and technological limitations involved. A fast Faraday cup measures longitudinal compression ratios greater than 50 with pulse durations less than 5 ns, in excellent agreement with reduced models and sophisticated simulations, which account for many experimental parameters and effects. The detailed physics of achieving current density compression in the laboratory is reviewed. Quantitative examples explore the dependency of longitudinal compression on effects such as the finite-size acceleration gap, voltage waveform accuracy, variation in initial beam temperature, pulse length, intended fractional velocity tilt, and energy uncertainty, as well as aberration within focusing elements and plasma neutralization processes. In addition, plasma evolution in experimental sources responsible for the degree of beam neutralization is studied numerically, since compression stagnation occurs under inadequate neutralization conditions, which may excite nonlinear collective excitations due to beam-plasma interactions. The design of simultaneous focusing experiments using both existing and upgraded hardware is provided, and parametric variations important for compression physics are

  16. Structure of the near-surface layer of NiTi on the meso- and microscale levels after ion-beam surface treatment

    SciTech Connect

    Meisner, L. L. Meisner, S. N.; Poletika, T. M. Girsova, S. L.; Tverdichlebova, A. V.; Shulepov, I. A.

    2014-11-14

    Using the EBSD, SEM and TEM methods, the structure of surface layer of polycrystalline NiTi alloy samples was examined after the modification of material surface by the pulsed action of mean-energy silicon ion beam. It was found that the ion beam treatment would cause grain fragmentation of the near-surface layer to a depth 5÷50 μm; a higher extent of fragmentation was observed in grains whose close-packed planes were oriented approximately in the same direction as the ion beam was. The effect of high-intensity ion beam treatment on the anisotropic behavior of polycrystalline NiTi alloy and the mechanisms involved were also examined.

  17. BEARS: Radioactive ion beams at LBNL

    SciTech Connect

    Powell, J.; Guo, F.Q.; Haustein, P.E.

    1998-07-01

    BEARS (Berkeley Experiments with Accelerated Radioactive Species) is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88 inch Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88 inch Cyclotron`s Electron Cyclotron Resonance (ECR) ion source. The first radioactive beams to be developed will include 20-min {sup 11}C and 70-sec {sup 14}O, produced by (p,n) and (p,{alpha}) reactions on low-Z targets. A test program is currently being conducted at the 88 inch Cyclotron to develop the parts of the BEARS system. Preliminary results of these tests lead to projections of initial {sup 11}C beams of up to 2.5 {times} 10{sup 7} ions/sec and {sup 14}O beams of 3 {times} 10{sup 5} ions/sec.

  18. The production of accelerated radioactive ion beams

    SciTech Connect

    Olsen, D.K.

    1993-11-01

    During the last few years, substantial work has been done and interest developed in the scientific opportunities available with accelerated radioactive ion beams (RIBs) for nuclear physics, astrophysics, and applied research. This interest has led to the construction, development, and proposed development of both first- and second-generation RIB facilities in Asia, North America, and Europe; international conferences on RIBs at Berkeley and Louvain-la-Neuve; and many workshops on specific aspects of RIB production and science. This paper provides a discussion of both the projectile fragmentation, PF, and isotope separator on-line, ISOL, approach to RIB production with particular emphasis on the latter approach, which employs a postaccelerator and is most suitable for nuclear structure physics. The existing, under construction, and proposed facilities worldwide are discussed. The paper draws heavily from the CERN ISOLDE work, the North American IsoSpin Laboratory (ISL) study, and the operating first-generation RIB facility at Louvain-la-Neuve, and the first-generation RIB project currently being constructed at ORNL.

  19. Infrared imaging diagnostics for INTF ion beam

    NASA Astrophysics Data System (ADS)

    Sudhir, D.; Bandyopadhyay, M.; Pandey, R.; Joshi, J.; Yadav, A.; Rotti, C.; Bhuyan, M.; Bansal, G.; Soni, J.; Tyagi, H.; Pandya, K.; Chakraborty, A.

    2015-04-01

    In India, testing facility named INTF [1] (Indian test facility) is being built in Institute for Plasma Research to characterize ITER-Diagnostic Neutral Beam (DNB). INTF is expected to deliver 60A negative hydrogen ion beam current of energy 100keV. The beam will be operated with 5Hz modulation having 3s ON/20s OFF duty cycle. To characterize the beam parameters several diagnostics are at different stages of design and development. One of them will be a beam dump, made of carbon fiber composite (CFC) plates placed perpendicular to the beam direction at a distance lm approximately. The beam dump needs to handle ˜ 6MW of beam power with peak power density ˜ 38.5MW/m2. The diagnostic is based on thermal (infra-red - IR) imaging of the footprint of the 1280 beamlets falling on the beam dump using four IR cameras from the rear side of the dump. The beam dump will be able to measure beam uniformity, beamlet divergence. It may give information on relative variation of negative ion stripping losses for different beam pulses. The design of this CFC based beam dump needs to address several physics and engineering issues, including some specific inputs from manufacturers. The manuscript will describe an overview of the diagnostic system and its design methodology highlighting those issues and the present status of its development.

  20. Ion beam sputter deposited zinc telluride films

    NASA Technical Reports Server (NTRS)

    Gulino, D. A.

    1985-01-01

    Zinc telluride is of interest as a potential electronic device material, particularly as one component in an amorphous superlattice, which is a new class of interesting and potentially useful materials. Some structural and electronic properties of ZnTe films deposited by argon ion beam sputter depoairion are described. Films (up to 3000 angstroms thick) were deposited from a ZnTe target. A beam energy of 1000 eV and a current density of 4 mA/sq. cm. resulted in deposition rates of approximately 70 angstroms/min. The optical band gap was found to be approximately 1.1 eV, indicating an amorphous structure, as compared to a literature value of 2.26 eV for crystalline material. Intrinsic stress measurements showed a thickness dependence, varying from tensile for thicknesses below 850 angstroms to compressive for larger thicknesses. Room temperature conductivity measurement also showed a thickness dependence, with values ranging from 1.86 x to to the -6/ohm. cm. for 300 angstrom film to 2.56 x 10 to the -1/ohm. cm. for a 2600 angstrom film. Measurement of the temperature dependence of the conductivity for these films showed complicated behavior which was thickness dependent. Thinner films showed at least two distinct temperature dependent conductivity mechanisms, as described by a Mott-type model. Thicker films showed only one principal conductivity mechanism, similar to what might be expected for a material with more crystalline character.

  1. Ion beam sputter deposited zinc telluride films

    NASA Technical Reports Server (NTRS)

    Gulino, D. A.

    1986-01-01

    Zinc telluride is of interest as a potential electronic device material, particularly as one component in an amorphous superlattice, which is a new class of interesting and potentially useful materials. Some structural and electronic properties of ZnTe films deposited by argon ion beam sputter deposition are described. Films (up to 3000 angstroms thick) were deposited from a ZnTe target. A beam energy of 1000 eV and a current density of 4 mA/sq cm resulted in deposition rates of approximately 70 angstroms/min. The optical band gap was found to be approximately 1.1 eV, indicating an amorphous structure, as compared to a literature value of 2.26 eV for crystalline material. Intrinsic stress measurements showed a thickness dependence, varying from tensile for thicknesses below 850 angstroms to compressive for larger thicknesses. Room temperature conductivity measurement also showed a thickness dependence, with values ranging from 1.86 x 10 to the -6th/ohm cm for 300 angstrom film to 2.56 x 10 to the -1/ohm cm for a 2600 angstrom film. Measurement of the temperature dependence of the conductivity for these films showed complicated behavior which was thickness dependent. Thinner films showed at least two distinct temperature dependent conductivity mechanisms, as described by a Mott-type model. Thicker films showed only one principal conductivity mechanism, similar to what might be expected for a material with more crystalline character.

  2. Image-projection ion-beam lithography

    SciTech Connect

    Miller, P.A.

    1989-01-01

    Image-projection ion-beam lithography promises high-throughput patterning with wide process latitude, excellent resolution, and minimal damage to underlying circuit layers. The process involves extracting helium ions from a plasma source, transmitting the ions at low voltage through a stencil reticle, and then accelerating and focusing the ions electrostatically onto the wafer. A key feature is the use of image demagnification which simplifies reticle fabrication and inspection, and leads to low power loading on the reticle and long reticle life. In this paper we report computational studies aimed at improving field size, linearity, and telecentricity over that demonstrated experimentally in the pioneering work by Ion Microfabrication Systems, GmbH (Vienna) during the past decade. We study a mechanically simple arrangement of equal-radii coaxial tubular lenses. We employ ion column optimization by simulated annealing and uncover a new optimization strategy which may be applicable in other optimization work. The resulting column design is much improved over our initial attempts based on an iterative optimization procedure. However, we still are unable to eliminate image distortion, and we would need either to rely on reticle predistortion or on use of a more complex electrode system for a production application. 15 refs., 5 figs.

  3. Titanium nitride deposited by dual ion beams

    NASA Astrophysics Data System (ADS)

    Ito, H.; Yoshida, Y.; Yamaji, S.; Maeyama, Y.; Ina, T.; Minowa, Y.

    1989-03-01

    Titanium nitride films have been prepared by the dual ion beam (DIB) deposition technique, which consists of the ionized cluster beam (ICB) and the ionized gas beam (IGB). As the source of ICB, vaporized titanium is ejected through the multinozzle of the crucible into a high vacuum chamber and is cooled and clustered by adiabatic expansion. The titanium clusters thus obtained are partially ionized in an electron shower and accelerated to the substrate. At the same time, as the source of IGB, nitrogen molecules are partially ionized, excited and decomposed in an electron shower and also accelerated to the substrate. These two beams collide and combine together on their way to the substrate. The characteristics of the ion current density and the properties of titanium nitride films are investigated. It is found that the DIB technique has a great advantage in preparing titanium nitride films of various crystalline structures from TiN to Ti 2N at a low temperature with a high deposition rate over a large substrate. Therefore, the chemical reaction is enhanced by the irradiation of the ionized and excited gases and the migration of ionized clusters on the substrate.

  4. Radially uniform circular sweep of ion beam

    SciTech Connect

    Akhmetov, T.D.; Davydenko, V.I.; Ivanov, A.A.; Kobets, V.V.; Medvedko, A.S.; Skorobogatov, D.N.; Tiunov, M.A.

    2006-03-15

    A spiral sweep of the ion beam was suggested to provide sufficiently uniform irradiation of a circular target. It is shown that if the beam radius is small enough, the radius of the beam center should increase as a square root of time to provide uniform radial irradiation of the target. In the complex for Boron Neutron Capture Therapy developed at the Budker Institute of Nuclear Physics, the proton beam sweep will be performed by a sweeper with uniform magnetic field with strength up to 500 G and axial length {approx}20 cm, rotating at 100-2000 Hz, and scanning over the radius at a 1-10 Hz frequency. The sweeper field is produced by four longitudinal flat current windings placed near the inner walls of a box-shaped yoke with the inner opening of a square cross section. A similar sweeping technique can be used in a 200 keV oxygen implanter, which is also under development at the Budker Institute.

  5. Microdosimetry in ion-beam therapy

    NASA Astrophysics Data System (ADS)

    Magrin, Giulio; Mayer, Ramona

    2015-05-01

    The information of the dose is not sufficiently describing the biological effects of ions on tissue since it does not express the radiation quality, i.e. the heterogeneity of the processes due to the slowing-down and the fragmentation of the particles when crossing a target. Depending on different circumstances, the radiation quality can be determined using measurements, calculations, or simulations. Microdosimeters are the primary tools used to provide the experimental information of the radiation quality and their role is becoming crucial for the recent clinical developments in particular with carbon ion therapy. Microdosimetry is strongly linked to the biological effectiveness of the radiation since it provides the physical parameters which explicitly distinguish the radiation for its capability of damaging cells. In the framework of ion-beam therapy microdosimetry can be used in the preparation of the treatment to complement radiobiological experiments and to analyze the modification of the radiation quality in phantoms. A more ambitious goal is to perform the measurements during the irradiation procedure to determine the non-targeted radiation and, more importantly, to monitor the modification of the radiation quality inside the patient. These procedures provide the feedback of the treatment directly beneficial for the single patient but also for the characterization of the biological effectiveness in general with advantages for all future treatment. Traditional and innovative tools are currently under study and an outlook of present experience and future development is presented here.

  6. Graphene engineering by neon ion beams.

    PubMed

    Iberi, Vighter; Ievlev, Anton V; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V; Joy, David C; Rondinone, Adam J; Belianinov, Alex; Ovchinnikova, Olga S

    2016-03-29

    Achieving the ultimate limits of lithographic resolution and material performance necessitates engineering of matter with atomic, molecular, and mesoscale fidelity. With the advent of scanning helium ion microscopy, maskless He(+) and Ne(+) beam lithography of 2D materials, such as graphene-based nanoelectronics, is coming to the forefront as a tool for fabrication and surface manipulation. However, the effects of using a Ne focused-ion-beam on the fidelity of structures created out of 2D materials have yet to be explored. Here, we will discuss the use of energetic Ne ions in engineering graphene nanostructures and explore their mechanical, electromechanical and chemical properties using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we are able to ascertain changes in the mechanical, electrical and optical properties of Ne(+) beam milled graphene nanostructures and surrounding regions. Additionally, we are able to link localized defects around the milled graphene to ion milling parameters such as dwell time and number of beam passes in order to characterize the induced changes in mechanical and electromechanical properties of the graphene surface. PMID:26890062

  7. Graphene engineering by neon ion beams.

    PubMed

    Iberi, Vighter; Ievlev, Anton V; Vlassiouk, Ivan; Jesse, Stephen; Kalinin, Sergei V; Joy, David C; Rondinone, Adam J; Belianinov, Alex; Ovchinnikova, Olga S

    2016-03-29

    Achieving the ultimate limits of lithographic resolution and material performance necessitates engineering of matter with atomic, molecular, and mesoscale fidelity. With the advent of scanning helium ion microscopy, maskless He(+) and Ne(+) beam lithography of 2D materials, such as graphene-based nanoelectronics, is coming to the forefront as a tool for fabrication and surface manipulation. However, the effects of using a Ne focused-ion-beam on the fidelity of structures created out of 2D materials have yet to be explored. Here, we will discuss the use of energetic Ne ions in engineering graphene nanostructures and explore their mechanical, electromechanical and chemical properties using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we are able to ascertain changes in the mechanical, electrical and optical properties of Ne(+) beam milled graphene nanostructures and surrounding regions. Additionally, we are able to link localized defects around the milled graphene to ion milling parameters such as dwell time and number of beam passes in order to characterize the induced changes in mechanical and electromechanical properties of the graphene surface.

  8. Intense ion beams accelerated by relativistic laser plasmas

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Cowan, Thomas E.; Gauthier, Jean-Claude J.; Allen, Matthew; Audebert, Patrick; Blazevic, Abel; Fuchs, Julien; Geissel, Matthias; Hegelich, Manuel; Karsch, S.; Meyer-ter-Vehn, Jurgen; Pukhov, Alexander; Schlegel, Theodor

    2001-12-01

    We have studied the influence of the target properties on laser-accelerated proton and ion beams generated by the LULI multi-terawatt laser. A strong dependence of the ion emission on the surface conditions, conductivity, shape and material of the thin foil targets were observed. We have performed a full characterization of the ion beam using magnetic spectrometers, Thompson parabolas, radiochromic film and nuclear activation techniques. The strong dependence of the ion beam acceleration on the conditions on the target back surface was found in agreement with theoretical predictions based on the target normal sheath acceleration (TNSA) mechanism. Proton kinetic energies up to 25 MeV have been observed.

  9. Ion-beam mixing in crystalline and amorphous germanium isotope multilayers

    SciTech Connect

    Bracht, H.; Radek, M.; Kube, R.; Knebel, S.; Posselt, M.; Schmidt, B.; Haller, E. E.; Bougeard, D.

    2011-11-01

    Gallium (Ga) implantation induced self-atom mixing in crystalline and amorphous germanium (Ge) is investigated utilizing isotopically controlled Ge multilayer structures grown by molecular beam epitaxy. The distribution of the Ga ions and the ion-beam induced depth-dependent mixing of the isotope structure was determined by means of secondary ion mass spectrometry. Whereas the distribution of Ga in the crystalline and amorphous Ge is very similar and accurately reproduced by computer simulations based on binary collision approximation (BCA), the ion-beam induced self-atom mixing is found to depend strongly on the state of the Ge structure. The experiments reveal stronger self-atom mixing in crystalline than in amorphous Ge. Atomistic simulations based on BCA reproduce the experimental results only when unphysically low Ge displacement energies are assumed. Analysis of the self-atom mixing induced by silicon implantation confirms the low displacement energy deduced within the BCA approach. This demonstrates that thermal spike mixing contributes significantly to the overall mixing of the Ge isotope structures. The disparity observed in the ion-beam mixing efficiency of crystalline and amorphous Ge indicates different dominant mixing mechanisms. We propose that self-atom mixing in crystalline Ge is mainly controlled by radiation enhanced diffusion during the early stage of mixing before the crystalline structure turns amorphous, whereas in an already amorphous state self-atom mixing is mediated by cooperative diffusion events.

  10. Perspectives of the Pixel Detector Timepix for Needs of Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Martišíková, M.; Hartmann, B.; Jäkel, O.; Granja, C.; Jakubek, J.

    2012-08-01

    Radiation therapy with ion beams is a highly precise kind of cancer treatment. In ion beam therapy the finite range of the ion beams in tissue and the increase of ionization density at the end of their path, the Bragg-peak, are exploited. Ions heavier than protons offer in addition increased biological effectiveness and decreased scattering. In this contribution we discuss the potential of a quantum counting and position sensitive semiconductor detector Timepix for its applications in ion beam therapy measurements. It provides high sensitivity and high spatial resolution (pixel pitch 55 μm). The detector, developed by the Medipix Collaboration, consists of a silicon sensor bump bonded to a pixelated readout chip (256 × 256 pixels with 55 μm pitch). An integrated USB-based readout interface together with the Pixelman software enable registering single particles online with 2D-track visualization. The experiments were performed at the Heidelberg Ion Beam Therapy Center (HIT), which is a modern ion beam therapy facility. Patient treatments are performed with proton and carbon ions, which are accelerated by a synchrotron. For dose delivery to the patient an active technique is used: narrow pencil-like beams are scanned over the target volume. The possibility to use the detector for two different applications was investigated: ion spectroscopy and beam delivery monitoring by measurement of secondary charged particles around the patient. During carbon ion therapy, a variety of ion species is created by nuclear fragmentation processes of the primary beam. Since they differ in their biological effectiveness, it is of large interest to measure the ion spectra created under different conditions and to visualize their spatial distribution. The possibility of measurements of ion energy loss in silicon makes Timepix a promising detector for ion-spectroscopic studies in patient-like phantoms. Unpredictable changes in the patient can alter the range of the ion beam in the body

  11. In situ nanomechanical testing in focused ion beam and scanning electron microscopes.

    PubMed

    Gianola, D S; Sedlmayr, A; Mönig, R; Volkert, C A; Major, R C; Cyrankowski, E; Asif, S A S; Warren, O L; Kraft, O

    2011-06-01

    The recent interest in size-dependent deformation of micro- and nanoscale materials has paralleled both technological miniaturization and advancements in imaging and small-scale mechanical testing methods. Here we describe a quantitative in situ nanomechanical testing approach adapted to a dual-beam focused ion beam and scanning electron microscope. A transducer based on a three-plate capacitor system is used for high-fidelity force and displacement measurements. Specimen manipulation, transfer, and alignment are performed using a manipulator, independently controlled positioners, and the focused ion beam. Gripping of specimens is achieved using electron-beam assisted Pt-organic deposition. Local strain measurements are obtained using digital image correlation of electron images taken during testing. Examples showing results for tensile testing of single-crystalline metallic nanowires and compression of nanoporous Au pillars will be presented in the context of size effects on mechanical behavior and highlight some of the challenges of conducting nanomechanical testing in vacuum environments.

  12. Energetic Ion Beam Production by a Low-Pressure Plasma Focus Discharge

    SciTech Connect

    Lim, L. K.; Yap, S. L.; Wong, C. S.

    2011-03-30

    Energetic ion beam emissions in a 3 kJ Mather type plasma focus operating at low-pressure regime are investigated. Deuterium gas is used and the discharge is operated in a low-pressure regime of below 1 mbar. Formation of the current sheath during the breakdown phase at the back wall is assisted by a set delayed trigger pulse. Energetic and intense ion beams with good reproducibility have been obtained for the operating pressure ranging from 0.05 mbar to 0.5 mbar. Deuteron beam is determined by time resolved measurement by making use of three biased ion collectors placed at the end on direction. The average energies of deuteron beams are resolved by using time-of flight method. Correlation between the ion emissions and the current sheath dynamics is also discussed.

  13. Investigation of the ion beam emission from a pulsed power plasma device

    NASA Astrophysics Data System (ADS)

    Henríquez, A.; Bhuyan, H.; Favre, M.; Retamal, M. J.; Volkmann, U.; Wyndham, E.; Chuaqui, H.

    2014-05-01

    Plasma Focus (PF) devices are well known as ion beam sources with characteristic energy among the hundreds of keV to tens of MeV. The information on ion beam energy, ion distribution and composition is essential from the viewpoint of understanding fundamental physics behind their production and acceleration and also their applications in various fields, such as surface properties modification, ion implantation, thin film deposition, semiconductor doping and ion assisted coating. An investigation from a low energy, 1.8 kJ 160 kA, Mather type plasma focus device operating with nitrogen using CR-39 detectors was conducted to study the emission of ions at different angular positions. Tracks on CR-39 detectors at different angular positions reveal the existence of angular ion anisotropy. The results obtained are comparable with the time integrated measurements using FC. Preliminary results of this work are presented.

  14. Improving the laser damage resistance of oxide thin films and multilayers via tailoring ion beam sputtering parameters

    NASA Astrophysics Data System (ADS)

    Cosar, M. B.; Ozhan, A. E. S.; Aydogdu, G. H.

    2015-05-01

    Ion beam sputtering is one of the widely used methods for manufacturing laser optical components due to its advantages such as uniformity, reproducibility, suitability for multilayer coatings and growth of dielectric materials with high packing densities. In this study, single Ta2O5 layers and Ta2O5/SiO2 heterostructures were deposited on optical quality glass substrates by dual ion beam sputtering. We focused on the effect of deposition conditions like substrate cleaning, assistance by 12 cm diameter ion beam source and oxygen partial pressure on the laser-induced damage threshold of Ta2O5 single layers. Afterwards, the obtained information is employed to a sample design and produces a Ta2O5/SiO2 multilayer structure demonstrating low laser-induced damage without a post treatment procedure.

  15. Controlled fabrication of silicon nanowires via nanosphere lithograph and metal assisted chemical etching.

    PubMed

    Sun, Bo; Shi, Tielin; Sheng, Wenjun; Liao, Guanglan

    2013-08-01

    We investigated the controlled fabrication of uniform vertical aligned silicon nanowires with desired length, diameter and location by combining nanosphere lithograph and metal assisted chemical etching techniques. The close-packed polystyrene nanospheres array was obtained by self-assemble technique, followed by reactive ion etching to acquire a non-close-packed monolayer template. Subsequently, the template was used to create a metal film with nanoholes array, which enable the controlled fabrication of ordered silicon nanowires via metal assisted chemical etching technique. By adjusting the monolayer of polystyrene nanospheres and the conditions for the metal assisted chemical etching, we obtained uniform distributed silicon nanowires with desired morphology. The aspect ratio of the silicon nanowires can reach to about 86:1. Furthermore, we have obtained the double-layer silicon nanowires by slight modifying the process. The influences of various conditions during etching were also discussed for improving the controlled fabrication.

  16. The assessment of microscopic charging effects induced by focused electron and ion beam irradiation of dielectrics.

    PubMed

    Stevens-Kalceff, Marion A; Levick, Katie J

    2007-03-01

    Energetic beams of electrons and ions are widely used to probe the microscopic properties of materials. Irradiation with charged beams in scanning electron microscopes (SEM) and focused ion beam (FIB) systems may result in the trapping of charge at irradiation induced or pre-existing defects within the implanted microvolume of the dielectric material. The significant perturbing influence on dielectric materials of both electron and (Ga(+)) ion beam irradiation is assessed using scanning probe microscopy (SPM) techniques. Kelvin Probe Microscopy (KPM) is an advanced SPM technique in which long-range Coulomb forces between a conductive atomic force probe and the silicon dioxide specimen enable the potential at the specimen surface to be characterized with high spatial resolution. KPM reveals characteristic significant localized potentials in both electron and ion implanted dielectrics. The potentials are observed despite charge mitigation strategies including prior coating of the dielectric specimen with a layer of thin grounded conductive material. Both electron- and ion-induced charging effects are influenced by a delicate balance of a number of different dynamic processes including charge-trapping and secondary electron emission. In the case of ion beam induced charging, the additional influence of ion implantation and nonstoichiometric sputtering from compounds is also important. The presence of a localized potential will result in the electromigration of mobile charged defect species within the irradiated volume of the dielectric specimen. This electromigration may result in local modification of the chemical composition of the irradiated dielectric. The implications of charging induced effects must be considered during the microanalysis and processing of dielectric materials using electron and ion beam techniques.

  17. Friction of self-lubricating surfaces by ion beam techniques. Final technical report

    SciTech Connect

    Bhattacharya, R.S.; Rai, A.K.

    1992-05-01

    UES, Inc. conducted a research and development program designed to establish conditions for ion implantation/mixing of suitable additives into the surfaces of bulk ceramics and metals for obtaining self-lubricating low friction and wear characteristics. The substrates considered were ZrO{sub 2}, Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4}, steel and Ni-base superalloy. The lubricant additives chosen were BaF{sub 2}/CaF{sub 2}Ag, MoS{sub 2}, WS{sub 2}and B{sub 2}O{sub 3}. The initial tasks of the program were to synthesis these lubricant compounds by co-implantation of constituent elements if sufficient beams of desired elements were obtained. The final tasks were to investigate high energy (MeV) ion mixing of deposited coatings as well as to investigate ion beam assisted deposition using low energy ion beams. It was shown that MoS{sub 2} can be synthesized by co-implantation of Mo{sup +} and S{sup +} in ceramic materials with appropriate choice of energies to obtain nearly overlapping depth profiles. The sliding life of DC magnetron sputtered MoS{sub 2} films of thicknesses {approximately}7500{Angstrom} on ceramic materials such as sapphire, Si{sub 3}N{sub 4} and ZrO{sub 3} were improved by ten to thousand fold after 2 Mev Ag{sup +} ion mixing. Ion beam assisted deposition (IBAD) and ion beam mixing were utilized to fabricate self-lubricating coatings of CaF{sub 2}/Ag and BaF/CaF{sub 2}/Ag composites.

  18. Nonlinear generation of whistler waves by an ion beam

    NASA Technical Reports Server (NTRS)

    Akimoto, K.; Winske, D.

    1989-01-01

    An electromagnetic hybrid code is used to simulate a new mechanism for whistler wave generation by an ion beam. First, a field-aligned ion beam becomes unstable to the electromagnetic ion/ion right-hand resonant instability which generates large amplitude MHD-like waves. These waves then trap the ion beam and increase its effective temperature anisotropy. As a result, the growth rates of the electron/whistler instability are significantly enhanced, and whistlers start to grow above the noise level. At the same time, because of the reduced parallel drift speed of the ion beam, the frequencies of the whistlers are also downshifted. Full simulations were performed to isolate and separately investigate the electron/ion whistler instability. The results are in agreement with the assumption of fluid electrons in the hybrid simulations and with the linear theory of the instability.

  19. Target fabrication for ion-beam driven hohlraum experiments

    SciTech Connect

    Aubert, J.H.; Sawyer, P.S.; Smith, M.L.

    1997-05-01

    Ion-beam driven hohlraum targets were designed to absorb the energy of PBFAII lithium ion beams within a foam, which converted the ion beam energy into x-rays. The foam was held within a gold hohlraum. X-ray radiation was observed from the top of the target through a circular diagnostic aperture. On the bottom of the target was a gold-coated aluminum witness plate, which was a component of an active, shock-breakout diagnostic. Surrounding the outside of the hohlraum were five titanium pins which produced ion-induced inner-shell x-rays (4.5 keV) to diagnose the lithium beam. Several different manufacturing processes and characterization techniques were utilized to prepare these targets. Extensive documentation provided quality control on their preparation. This report summarizes the preparation, characterization, and documentation of targets for ion-beam driven hohlraum experiments.

  20. Ion beam requirements for fast ignition of inertial fusion targets

    SciTech Connect

    Honrubia, J. J.; Murakami, M.

    2015-01-15

    Ion beam requirements for fast ignition are investigated by numerical simulation taking into account new effects, such as ion beam divergence, not included before. We assume that ions are generated by the TNSA scheme in a curved foil placed inside a re-entrant cone and focused on the cone apex or beyond. From the focusing point to the compressed core, ions propagate with a given divergence angle. Ignition energies are obtained for two compressed fuel configurations heated by proton and carbon ion beams. The dependence of the ignition energies on the beam divergence angle and on the position of the ion beam focusing point has been analyzed. Comparison between TNSA and quasi-monoenergetic ions is also shown.

  1. Use of energetic ion beams in materials synthesis and processing

    SciTech Connect

    Appleton, B R

    1991-01-01

    A brief review of the use energetic ion beams and related techniques for the synthesis, processing, and characterization of materials is presented. Selected opportunity areas are emphasized with examples, and references are provided for more extensive coverage.

  2. Ion beam energy deposition physics for ICF targets

    SciTech Connect

    Mehlhorn, T.A.

    1980-01-01

    The target interaction physics of light ion beams will be described. The phenomenon of range shortening with increasing material temperature will be corroborated, and the concomittant phenomenon of range relengthening due to ion-electron decoupling will be introduced.

  3. Novel patterns by focused ion beam guided anodization.

    PubMed

    Chen, Bo; Lu, Kathy; Tian, Zhipeng

    2011-01-18

    Focused ion beam patterning is a powerful technique for guiding the growth of ordered hexagonal porous anodic alumina. This study shows that, with the guidance of the focused ion beam patterning, hexagonal porous anodic alumina with interpore distances from 200 to 425 nm can be fabricated at 140 V in 0.3 M phosphoric acid. When the interpore distance is increased to 500 nm, alternating diameter nanopore arrays are synthesized with the creation and growth of new small pores at the junctions of three large neighboring pores. Moreover, alternating diameter nanopore arrays in hexagonal arrangement are fabricated by focused ion beam patterning guided anodization. Interpore distance is an important parameter affecting the arrangement of alternating diameter nanopore arrays. Different types of novel patterns are obtained by designing different focused ion beam concave arrays. The fundamental understanding of the process is discussed.

  4. Biophysical models in ion beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Scholz, Michael; Elsässer, Thilo

    One major rationale for the application of heavy ion beams in tumor therapy is their increased relative biological effectiveness (RBE) in the Bragg peak region. For dose prescription, the increased effectiveness has to be taken into account in treatment planning. Hence, the complex dependencies of RBE on the dose level, biological endpoint, position in the field etc. require biophysical models, which have to fulfill two important criteria: simplicity and quantitative precision. Simplicity means that the number of free parameters should be kept at a minimum. Due to the lack of precise quantitative data, at least at present, this requirement is incompatible with approaches aiming at the molecular modeling of the whole chain of production, processing and repair of biological damages. Quantitative precision is required since steep gradients in the dose response curves are observed for most tumor and normal tissues; thus, even small uncertainties in the estimation of the biologically effective dose can transform into large uncertainties in the clinical outcome. The paper will give a general introduction into the field, followed by a description of a specific model, the so called 'Local Effect Model' (LEM). This model has been successfully applied within treatment planning in the GSI pilot project for carbon ion tumor therapy over almost 10 years now. The model is based on the knowledge of charged particle track structure in combination with the response of the cells or tissues under consideration to conventional photon radiation. The model is compared to other approaches developed for the calculation of the biological effects of high-LET radiation. Furthermore, recent improvements of the model are described. Due to the quantitative precision, besides applications in tumor therapy the LEM seems to be adequate for the calculation of stochastic radiation effects, i.e. in the framework of radiation protection. Examples for the calculation of cell transformation are

  5. An ion beam analysis software based on ImageJ

    NASA Astrophysics Data System (ADS)

    Udalagama, C.; Chen, X.; Bettiol, A. A.; Watt, F.

    2013-07-01

    The suit of techniques (RBS, STIM, ERDS, PIXE, IL, IF,…) available in ion beam analysis yields a variety of rich information. Typically, after the initial challenge of acquiring data we are then faced with the task of having to extract relevant information or to present the data in a format with the greatest impact. This process sometimes requires developing new software tools. When faced with such situations the usual practice at the Centre for Ion Beam Applications (CIBA) in Singapore has been to use our computational expertise to develop ad hoc software tools as and when we need them. It then became apparent that the whole ion beam community can benefit from such tools; specifically from a common software toolset that can be developed and maintained by everyone with freedom to use and allowance to modify. In addition to the benefits of readymade tools and sharing the onus of development, this also opens up the possibility for collaborators to access and analyse ion beam data without having to depend on an ion beam lab. This has the virtue of making the ion beam techniques more accessible to a broader scientific community. We have identified ImageJ as an appropriate software base to develop such a common toolset. In addition to being in the public domain and been setup for collaborative tool development, ImageJ is accompanied by hundreds of modules (plugins) that allow great breadth in analysis. The present work is the first step towards integrating ion beam analysis into ImageJ. Some of the features of the current version of the ImageJ ‘ion beam' plugin are: (1) reading list mode or event-by-event files, (2) energy gates/sorts, (3) sort stacks, (4) colour function, (5) real time map updating, (6) real time colour updating and (7) median & average map creation.

  6. Rapid Coarsening of Ion Beam Ripple Patterns by Defect Annihilation

    SciTech Connect

    Hansen, Henri; Messlinger, Sebastian; Stoian, Georgiana; Redinger, Alex; Krug, Joachim; Michely, Thomas

    2009-04-10

    Ripple patterns formed on Pt(111) through grazing incidence ion beam erosion coarsen rapidly. At and below 450 K coarsening of the patterns is athermal and kinetic, unrelated to diffusion and surface free energy. Similar to the situation for sand dunes, coarsening takes place through annihilation reactions of mobile defects in the pattern. The defect velocity derived on the basis of a simple model agrees quantitatively with the velocity of monatomic steps illuminated by the ion beam.

  7. A preliminary model of ion beam neutralization. [in thruster plasmas

    NASA Technical Reports Server (NTRS)

    Parks, D. E.; Katz, I.

    1979-01-01

    A theoretical model of neutralized thruster ion beam plasmas has been developed. The basic premise is that the beam forms an electrostatic trap for the neutralizing electrons. A Maxwellian spectrum of electron energies is maintained by collisions between trapped electrons and by collective randomization of velocities of electrons injected from the neutralizer into the surrounding plasma. The theory contains the observed barometric law relationship between electron density and electron temperatures and ion beam spreading in good agreement with measured results.

  8. Ion Beam Synthesis of Transition Metal Nanoclusters in Silicon

    SciTech Connect

    Wesch, W.; Picht, O.; Steinert, M.; Undisz, A.; Rettenmayr, M.; Kaiser, U.; Biskupek, J.; Sobolev, N. A.

    2009-03-10

    The synthesis of materials combining ferromagnetism and semiconducting properties is of great interest for the development of devices for future electronics. Possible implementations of adding the spin degree of freedom to conventional semiconductors are the formation of diluted magnetic semiconductors (DMS's) and the synthesis of magnetic clusters embedded in semiconducting matrices. Despite the technological importance of Si, the former research has mostly been focused on II-VI, III-V and other compound semiconductors. Beside various layer deposition techniques, ion implantation in combination with subsequent thermal treatment is an excellent way to introduce the necessary high concentration of foreign atoms into the substrate. Especially the formation of magnetic clusters in semiconductors or DMS layers is of interest because they offer the possibility to achieve Curie temperatures above room temperature, which is a drawback of common DMS structures. In the present paper we have studied the formation of MnAs and MnSb nanoclusters in Si by co-implantation of Mn, As and Sb in combination with subsequent thermal annealing. In certain windows of the implantation and annealing parameters both Mn and As or Mn and Sb rich crystalline nanoclusters are formed that are partly phase-separated. The influence of the formation parameters on size, size distribution and composition of the nanocrystals as well as the role of atom diffusion are discussed. Results of magnetic analyses are presented as well.

  9. High intensity ion beam injection into the 88-inch cyclotron

    SciTech Connect

    Wutte, Daniela; Clark, Dave J.; Laune, Bernard; Leitner,Matthaeus A.; Lyneis, Claude M.

    2000-05-31

    Low cross section experiments to produce super-heavyelements have increased the demand for high intensity heavy ion beams atenergies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the LawrenceBerkeley National Laboratory. Therefore, efforts are underway to increasethe overall ion beam transmission through the axial injection line andthe cyclotron. The ion beam emittance has been measured for various ionmasses and charge states. Beam transport simulations including spacecharge effects were performed for both of the injection line and the ionsource extraction. The relatively low nominal injection voltage of 10 kVwas found to be the main factor for ion beam losses, because of beam blowup due to space charge forces at higher intensities. Consequently,experiments and simulations have been performed at higherinjectionenergies, and it was demonstrated that the ion beams could still becentered in the cyclotron at these energies. Therefore, the new injectorion source VENUS and its ion beam transport system (currently underconstruction at the 88-Inch Cyclotron) are designed for extractionvoltages up to 30 kV.

  10. In-plane texturing control of Y-Ba-Cu-O thin films on polycrystalline substrates by ion-beam-modified intermediate buffer layers

    NASA Astrophysics Data System (ADS)

    Iijima, Y.; Onabe, K.; Futaki, N.; Tanabe, N.; Sadakata, N.; Kohno, O.; Ikeno, Y.

    1993-03-01

    Biaxially aligned YBCO thin films were successfully formed on polycrystalline Ni-based alloy by using ion-beam-modified yttria-stabilized-zirconia (YSZ) intermediate layers. YSZ layers were deposited by ion-beam-assisted deposition (IBAD) with concurrent off-axis ion beam bombardment. The YSZ 100-line axis was oriented normal to the substrate, and a YSZ 111-line axis was aligned to the bombarding ion beam axis. Explicit in-plane ordering was achieved on polycrystalline metallic substrates without epitaxial relationships. C-axis-oriented YBCO thin films were grown on those buffer layers, with controlled in-plane a- and b-axes, by pulsed laser deposition. At 77 K, 0 T and at 77 K, 0.6 T, 4.3 x 10 exp 5 A/sq cm and 1.1 x 10 exp 5 A/sq cm were achieved, respectively.

  11. Improve the corrosion and cytotoxic behavior of NiTi implants with use of the ion beam technologies

    SciTech Connect

    Meisner, L. L. Meisner, S. N.; Matveeva, V. A.; Matveev, A. L.

    2015-11-17

    The corrosion resistance behavior and cytotoxicity of binary NiTi-base alloy specimens subjected to surface modification by silicon ion beams and the proliferative ability of mesenchymal stem cells (MSC) of rat marrow on an ion-implanted surface of the alloy have been studied. The silicon ion beam processing of specimen surfaces is shown to bring about a nearly two-fold improvement in the corrosion resistance of the material to attack by acqueous solutions of NaCl and human plasma and a drastic decrease in the nickel concentration after immersion of the specimens into the solutions for ∼3400 and ∼6000 h, respectively. It is found that MSC proliferation strongly depends on the surface structure, roughness and chemical condition of NiTi implants.

  12. Improve the corrosion and cytotoxic behavior of NiTi implants with use of the ion beam technologies

    NASA Astrophysics Data System (ADS)

    Meisner, L. L.; Matveeva, V. A.; Meisner, S. N.; Matveev, A. L.

    2015-11-01

    The corrosion resistance behavior and cytotoxicity of binary NiTi-base alloy specimens subjected to surface modification by silicon ion beams and the proliferative ability of mesenchymal stem cells (MSC) of rat marrow on an ion-implanted surface of the alloy have been studied. The silicon ion beam processing of specimen surfaces is shown to bring about a nearly two-fold improvement in the corrosion resistance of the material to attack by acqueous solutions of NaCl and human plasma and a drastic decrease in the nickel concentration after immersion of the specimens into the solutions for ˜3400 and ˜6000 h, respectively. It is found that MSC proliferation strongly depends on the surface structure, roughness and chemical condition of NiTi implants.

  13. Mechanical and tribological properties of ion beam-processed surfaces

    SciTech Connect

    Kodali, P.

    1998-01-01

    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness.

  14. Copper-assisted, anti-reflection etching of silicon surfaces

    SciTech Connect

    Toor, Fatima; Branz, Howard

    2014-08-26

    A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

  15. Bright focused ion beam sources based on laser-cooled atoms

    PubMed Central

    McClelland, J. J.; Steele, A. V.; Knuffman, B.; Twedt, K. A.; Schwarzkopf, A.; Wilson, T. M.

    2016-01-01

    Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future. PMID:27239245

  16. Bright focused ion beam sources based on laser-cooled atoms

    NASA Astrophysics Data System (ADS)

    McClelland, J. J.; Steele, A. V.; Knuffman, B.; Twedt, K. A.; Schwarzkopf, A.; Wilson, T. M.

    2016-03-01

    Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review, we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.

  17. Epitaxial GaN films by hyperthermal ion-beam nitridation of Ga droplets

    SciTech Connect

    Gerlach, J. W.; Ivanov, T.; Neumann, L.; Hoeche, Th.; Hirsch, D.; Rauschenbach, B.

    2012-06-01

    Epitaxial GaN film formation on bare 6H-SiC(0001) substrates via the process of transformation of Ga droplets into a thin GaN film by applying hyperthermal nitrogen ions is investigated. Pre-deposited Ga atoms in well defined amounts form large droplets on the substrate surface which are subsequently nitridated at a substrate temperature of 630 Degree-Sign C by a low-energy nitrogen ion beam from a constricted glow-discharge ion source. The Ga deposition and ion-beam nitridation process steps are monitored in situ by reflection high-energy electron diffraction. Ex situ characterization by x-ray diffraction and reflectivity techniques, Rutherford backscattering spectrometry, and electron microscopy shows that the thickness of the resulting GaN films depends on the various amounts of pre-deposited gallium. The films are epitaxial to the substrate, exhibit a mosaic like, smooth surface topography and consist of coalesced large domains of low defect density. Possible transport mechanisms of reactive nitrogen species during hyperthermal nitridation are discussed and the formation of GaN films by an ion-beam assisted process is explained.

  18. Patient position verification in ion-beam therapy using ion-beam radiography and fiducial markers

    NASA Astrophysics Data System (ADS)

    Huber, Lucas; Telsemeyer, Julia; Martišíková, Mária; Jäkel, Oliver

    2011-11-01

    The basic rationale for radiation therapy using ion-beams is its high local precision of dose deposition. Therefore accurate patient positioning prior to and during beam application is a crucial part of the therapy. The current standard position verification procedure uses X-ray based imaging before each beam application. The patient is assumed to remain in his position throughout irradiation. Currently there is no monitoring of the patient position or organ movement during treatment. The aim of this study is to investigate the possibility of verifying the position of a fiducial marker during therapy using ion radiography. Some modern ion therapy facilities like the Heidelberg Ion-Beam Therapy Center (HIT), where our measurements were carried out, use scanning pencil beams to apply dose. Exploiting them for imaging allows to solely irradiate regions of interest in the patient's body, e.g. tissue containing medical markers. The advantage of this technique is that it can be performed quickly in turn with therapeutic beam application and irradiates only very little tissue. For our measurements we used conventional medical metal markers embedded in phantom material mimicking body tissue. To image the residual beam we use a Perkin Elmer RID256-L flat panel detector. In an idealized setup the marker contrast was measured to be as high as 60%, which was reduced by a factor of 2-2.5 when the marker was placed at distances to the detector in the phantom material larger than 10 cm. It was shown that applying 2ṡ105 carbon ions suffices to make the markers' position visible in a setup of realistic material thickness and marker depth. While the dose is comparable to X-ray imaging, the irradiated volume and, consequently, also the integral dose is considerably reduced. However, in realistic geometries there are large particle range differences in lateral direction yielding steep signal gradients in the radiography. Thus, the useful image area with unambiguous signal

  19. Measurement of secondary radiation during ion beam therapy with the pixel detector Timepix

    NASA Astrophysics Data System (ADS)

    Martišíková, Mária; Jakubek, Jan; Granja, Carlos; Hartmann, Bernadette; Opálka, Lukáš; Pospíšil, Stanislav; Jäkel, Oliver

    2011-11-01

    In ion beam therapy the finite range of the ion beams in tissue and the presence of the Bragg-peak are exploited. Unpredictable changes in the patient`s condition can alter the range of the ion beam in the body. Therefore it is desired to verify the actual ion range during the treatment, preferably in a non-invasive way. Positron emission tomography (PET) has been used successfully to monitor the applied dose distributions. This method however suffers from limited applicability and low detection efficiency. In order to increase the detection efficiency and to decrease the uncertainties, in this study we investigate the possibility to measure secondary charged particles emerging from the patient during irradiation. An initial experimental study to register the particle radiation coming out of a patient phantom during the therapy was performed at the Heidelberg Ion Beam Therapy Center (HIT) in Germany. A static narrowly-focused beam of carbon ions was directed into a head phantom. The emerging secondary radiation was measured with the position-sensitive Timepix detector outside of the phantom. The detector, developed by the Medipix Collaboration, consists of a silicon sensor bump bonded to a pixelated readout chip (256 × 256 pixels with 55 μm pitch). Together with the USB-based readout interface, Timepix can operate as an active nuclear emulsion registering single particles online with 2D-track visualization. In this contribution we measured the signal behind the head phantom and investigated its dependence on the beam energy (corresponding to beam range in water 2-30 cm). Furthermore, the response was measured at four angles between 0 and 90 degrees. At all investigated energies some signal was registered. Its pattern corresponds to ions. Differences in the total amount of signal for different beam energies were observed. The time-structure of the signal is correlated with that of the incoming beam, showing that we register products of prompt processes. Such

  20. Electron-Cloud Effects on Heavy-Ion Beams

    SciTech Connect

    Azevedo, T; Friedman, A; Cohen, R; Vay, J

    2004-03-29

    Stray electrons can be introduced in positive-charge accelerators for heavy ion fusion (or other applications) as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary-electron emission. We are developing a capability for self-consistent simulation of ion beams with the electron clouds they produce. We report on an ingredient in this capability, the effect of specified electron cloud distributions on the dynamics of a coasting ion beam. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing mode frequencies, the centroid and shape perturbations can also be effective. We identify a possible instability associated with resonance with the beam-envelope ''breathing'' mode. One conclusion from this study is that heavy-ion beams are surprisingly robust to electron clouds, compared to a priori expectations.

  1. Intense ion beams accelerated by ultra-intense laser pulses

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Cowan, T. E.; Gauthier, J. C.; Vehn, J. Meyer-Ter; Allen, M.; Audebert, P.; Blazevic, A.; Fuchs, J.; Geissel, M.; Hegelich, M.; Karsch, S.; Pukhov, A.; Schlegel, T.

    2002-04-01

    The discovery of intense ion beams off solid targets irradiated by ultra-intense laser pulses has become the subject of extensive international interest. These highly collimated, energetic beams of protons and heavy ions are strongly depending on the laser parameters as well as on the properties of the irradiated targets. Therefore we have studied the influence of the target conditions on laser-accelerated ion beams generated by multi-terawatt lasers. The experiments were performed using the 100 TW laser facility at Laboratoire pour l'Utilisation des Laser Intense (LULI). The targets were irradiated by pulses up to 5×1019 W/cm2 (~300 fs,λ=1.05 μm) at normal incidence. A strong dependence on the surface conditions, conductivity, shape and purity was observed. The plasma density on the front and rear surface was determined by laser interferometry. We characterized the ion beam by means of magnetic spectrometers, radiochromic film, nuclear activation and Thompson parabolas. The strong dependence of the ion beam acceleration on the conditions on the target back surface was confirmed in agreement with predictions based on the target normal sheath acceleration (TNSA) mechanism. Finally shaping of the ion beam has been demonstrated by the appropriate tailoring of the target. .

  2. Ion-beam assisted laser fabrication of sensing plasmonic nanostructures

    PubMed Central

    Kuchmizhak, Aleksandr; Gurbatov, Stanislav; Vitrik, Oleg; Kulchin, Yuri; Milichko, Valentin; Makarov, Sergey; Kudryashov, Sergey

    2016-01-01

    Simple high-performance, two-stage hybrid technique was developed for fabrication of different plasmonic nanostructures, including nanorods, nanorings, as well as more complex structures on glass substrates. In this technique, a thin noble-metal film on a dielectric substrate is irradiated by a single tightly focused nanosecond laser pulse and then the modified region is slowly polished by an accelerated argon ion (Ar+) beam. As a result, each nanosecond laser pulse locally modifies the initial metal film through initiation of fast melting and subsequent hydrodynamic processes, while the following Ar+-ion polishing removes the rest of the film, revealing the hidden topography features and fabricating separate plasmonic structures on the glass substrate. We demonstrate that the shape and lateral size of the resulting functional plasmonic nanostructures depend on the laser pulse energy and metal film thickness, while subsequent Ar+-ion polishing enables to vary height of the resulting nanostructures. Plasmonic properties of the fabricated nanostructures were characterized by dark-field micro-spectroscopy, Raman and photoluminescence measurements performed on single nanofeatures, as well as by supporting numerical calculations of the related electromagnetic near-fields and Purcell factors. The developed simple two-stage technique represents a new step towards direct large-scale laser-induced fabrication of highly ordered arrays of complex plasmonic nanostructures. PMID:26776569

  3. Ohmic heated sheet for the Ca ion beam production.

    PubMed

    Efremov, A; Bogomolov, S; Kazarinov, N; Kochagov, O; Loginov, V

    2008-02-01

    The production of intense accelerated (48)Ca ion beams is the key problem in the experiments on the synthesis of new superheavy nuclei. For this purpose in the FLNR (JINR), an electron cyclotron resonance ion source is used at the U-400 cyclotron. The combination of a micro oven with a hot tantalum sheet inside the discharge chamber allowed the production of the intense (48)Ca(5+) ion beam at the (48)Ca consumption of about 0.5 mg/h. In this case, the tantalum sheet is heated by microwaves and plasma electrons. The microwave power of up to 500 W is required to heat the sheet to the temperature of about 500 degrees C. To decrease the required microwave power, a new sheet with a direct Ohmic heating was designed. The present paper describes the method, technique, and preliminary experimental results on the production of the Ca ion beam.

  4. Fast ion beam chopping system for neutron generators

    NASA Astrophysics Data System (ADS)

    Hahto, S. K.; Hahto, S. T.; Leung, K. N.; Reijonen, J.; Miller, T. G.; Van Staagen, P. K.

    2005-02-01

    Fast deuterium (D+) and tritium (T+) ion beam pulses are needed in some neutron-based imaging systems. A compact, integrated fast ion beam extraction and chopping system has been developed and tested at the Lawrence Berkeley National Laboratory for these applications, and beam pulses with 15ns full width at half maximum have been achieved. Computer simulations together with experimental tests indicate that even faster pulses are achievable by shortening the chopper voltage rise time. This chopper arrangement will be implemented in a coaxial neutron generator, in which a small point-like neutron source is created by multiple 120keV D+ ion beams hitting a titanium target at the center of the source.

  5. Fast ion beam chopping system for neutron generators

    SciTech Connect

    Hahto, S.K.; Hahto, S.T.; Leung, K.N.; Reijonen, J.; Miller, T.G.; Van Staagen, P.K.

    2005-02-01

    Fast deuterium (D{sup +}) and tritium (T{sup +}) ion beam pulses are needed in some neutron-based imaging systems. A compact, integrated fast ion beam extraction and chopping system has been developed and tested at the Lawrence Berkeley National Laboratory for these applications, and beam pulses with 15 ns full width at half maximum have been achieved. Computer simulations together with experimental tests indicate that even faster pulses are achievable by shortening the chopper voltage rise time. This chopper arrangement will be implemented in a coaxial neutron generator, in which a small point-like neutron source is created by multiple 120 keV D{sup +} ion beams hitting a titanium target at the center of the source.

  6. Lithium ion beam driven hohlraums for PBFA II

    SciTech Connect

    Dukart, R.J.

    1994-05-06

    In our light ion inertial confinement fusion (ICF) program, fusion capsules are driven with an intense x-ray radiation field produced when an intense beam of ions penetrates a radiation case and deposits energy in a foam x-ray conversion region. A first step in the program is to generate and measure these intense fields on the Particle Beam Fusion Accelerator II (PBFA II). Our goal is to generate a 100-eV radiation temperature in lithium ion beam driven hohlraums, the radiation environment which will provide the initial drive temperature for ion beam driven implosion systems designed to achieve high gain. In this paper, we describe the design of such hohlraum targets and their predicted performance on PBFA II as we provide increasing ion beam intensities.

  7. Surface modification using low energy ground state ion beams

    NASA Technical Reports Server (NTRS)

    Chutjian, Ara (Inventor); Hecht, Michael H. (Inventor); Orient, Otto J. (Inventor)

    1990-01-01

    A method of effecting modifications at the surfaces of materials using low energy ion beams of known quantum state, purity, flux, and energy is presented. The ion beam is obtained by bombarding ion-generating molecules with electrons which are also at low energy. The electrons used to bombard the ion generating molecules are separated from the ions thus obtained and the ion beam is directed at the material surface to be modified. Depending on the type of ion generating molecules used, different ions can be obtained for different types of surface modifications such as oxidation and diamond film formation. One area of application is in the manufacture of semiconductor devices from semiconductor wafers.

  8. Neutralization tests on the SERT II spacecraft. [of ion beams

    NASA Technical Reports Server (NTRS)

    Kerslake, W. R.; Domitz, S.

    1979-01-01

    Orbit precession returned the SERT II spacecraft to continuous sunlight in January 1979 for the first time since early 1972, and new experiments were planned and conducted. Neutralization of an ion beam was accomplished by a second neutralizer cathode located 1 meter away. Plasma potential measurements were made of the plasma surrounding the ion beam and connecting the beam to the second neutralizer. When the density of the connecting plasma was increased by turning on the main discharge of a neighboring ion thruster, the neutralization of the ion beam occurred with improved (lower) coupling voltage. These and other tests reported should aid in the future design of spacecraft using electric thruster systems. Data taken indicate that cross neutralization of ion thrusters in a multiple thruster array should occur readily.

  9. Mutation induced with ion beam irradiation in rose

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Nagatomi, S.; Morishita, T.; Degi, K.; Tanaka, A.; Shikazono, N.; Hase, Y.

    2003-05-01

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

  10. Ion beam mixing in Ag-Pd alloys

    NASA Astrophysics Data System (ADS)

    Klatt, J. L.; Averback, R. S.; Peak, David

    1989-09-01

    Ion beam mixing during 750 keV Kr+ irradiation at 80 K was measured on a series of Ag-Pd alloys using Au marker atoms. The mixing in pure Ag was the greatest and it decreased monotonically with increasing Pd content, being a factor of 10 higher in pure Ag than in pure Pd. This large difference in mixing cannot be explained by the difference in cohesion energy between Ag and Pd in the thermodynamic model of ion beam mixing proposed by Johnson et al. [W. L. Johnson, Y. T. Cheng, M. Van Rossum, and M-A. Nicolet, Nucl. Instrum. Methods B 7/8, 657 (1985)]. An alternative model based on local melting in the cascade is shown to account for the ion beam mixing results in Ag and Pd.

  11. Annealing of TiO2 Films Deposited on Si by Irradiating Nitrogen Ion Beams

    SciTech Connect

    Yokota, Katsuhiro; Yano, Yoshinori; Miyashita, Fumiyoshi

    2006-11-13

    Thin TiO2 films were deposited on Si at a temperature of 600 deg. C by an ion beam assisted deposition (IBAD) method. The TiO2 films were annealed for 30 min in Ar at temperatures below 700 deg. C. The as-deposited TiO2 films had high permittivities such 200 {epsilon}o and consisted of crystallites that were not preferentially oriented to the c-axis but had an expanded c-axis. On the annealed TiO2 films, permittivities became lower with increasing annealing temperature, and crystallites were oriented preferentially to the (110) plane.

  12. Low energy ion beam dynamics of NANOGAN ECR ion source

    NASA Astrophysics Data System (ADS)

    Kumar, Sarvesh; Mandal, A.

    2016-04-01

    A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

  13. EBIS charge breeder for radioactive ion beams at ATLAS.

    SciTech Connect

    Ostroumov, P.; Kondrashev, S.; Pardo, R.; Savard, G.; Vondrasek, R.; Alessi, J.; Beebe, E.; Pikin, A.

    2010-07-01

    The construction of the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne National Laboratory ATLAS facility is completed and its commissioning is being performed. In its full capacity, the CARIBU facility will use fission fragments from a 1 Curie (Ci) {sup 252}Cf source. The ions will be thermalized and collected into a low-energy ion beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred to higher charge states for acceleration in ATLAS. To reach energies E/A 10 MeV/u, one should inject ions with charge-to-mass ratio (q/A) {ge} 1/7 into the ATLAS linac. In the first stage, the existing Electron Cyclotron Resonance (ECR) ion source will be used as a charge breeder. The maximum intensity of radioactive ion beams at the output of the gas catcher will not exceed 10{sup 7} ions per second. A charge breeder based on an Electron Beam Ion Source (EBIS) has significant advantages over the ECR option for ion beam intensities up to about 10{sup 9} ions per second, providing 3-4 times higher efficiency and significantly better purity of highly charged radioactive ion beams for further acceleration. The proposed EBIS project for CARIBU will heavily utilize state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory. This will allow us to reduce both the project cost and timescale, simultaneously insuring reliable technical realization of the cutting-edge technology. Several parameters of the CARIBU EBIS charge breeder (EBIS-CB) will be relaxed with respect to the BNL EBIS in favor of higher reliability and lower cost. Technical performance of the CARIBU charge breeder will not suffer from such a relaxation and will provide high efficiency for a whole range of radioactive ion beams. The goal of this paper is to present the initial design of the EBIS charge breeder for radioactive ion beams at ATLAS.

  14. EBIS charge breeder for radioactive ion beams at ATLAS

    NASA Astrophysics Data System (ADS)

    Ostroumov, P.; Kondrashev, S.; Pardo, R.; Savard, G.; Vondrasek, R.; Alessi, J.; Beebe, E.; Pikin, A.

    2010-07-01

    The construction of the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne National Laboratory ATLAS facility is completed and its commissioning is being performed. In its full capacity, the CARIBU facility will use fission fragments from a 1 Curie (Ci) 252Cf source. The ions will be thermalized and collected into a low-energy ion beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred to higher charge states for acceleration in ATLAS. To reach energies E/A 10 MeV/u, one should inject ions with charge-to-mass ratio (q/A) >= 1/7 into the ATLAS linac. In the first stage, the existing Electron Cyclotron Resonance (ECR) ion source will be used as a charge breeder. The maximum intensity of radioactive ion beams at the output of the gas catcher will not exceed 107 ions per second. A charge breeder based on an Electron Beam Ion Source (EBIS) has significant advantages over the ECR option for ion beam intensities up to about 109 ions per second, providing 3-4 times higher efficiency and significantly better purity of highly charged radioactive ion beams for further acceleration. The proposed EBIS project for CARIBU will heavily utilize state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory. This will allow us to reduce both the project cost and timescale, simultaneously insuring reliable technical realization of the cutting-edge technology. Several parameters of the CARIBU EBIS charge breeder (EBIS-CB) will be relaxed with respect to the BNL EBIS in favor of higher reliability and lower cost. Technical performance of the CARIBU charge breeder will not suffer from such a relaxation and will provide high efficiency for a whole range of radioactive ion beams. The goal of this paper is to present the initial design of the EBIS charge breeder for radioactive ion beams at ATLAS.

  15. EBIS charge breeder for radioactive ion beams at ATLAS

    SciTech Connect

    Ostroumov, P.; Alessi, J.; Kondrashev, S.; Pardo, R.; Savard, G.; Vondrasek, R.; Beebe, E.; Pikin, A.

    2010-07-20

    The construction of the Californium Rare Isotope Breeder Upgrade (CARIBU) for the Argonne National Laboratory ATLAS facility is completed and its commissioning is being performed. In its full capacity, the CARIBU facility will use fission fragments from a 1 Curie (Ci) {sup 252}Cf source. The ions will be thermalized and collected into a low-energy ion beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred to higher charge states for acceleration in ATLAS. To reach energies E/A 10 MeV/u, one should inject ions with charge-to-mass ratio (q/A) {ge} 1/7 into the ATLAS linac. In the first stage, the existing Electron Cyclotron Resonance (ECR) ion source will be used as a charge breeder. The maximum intensity of radioactive ion beams at the output of the gas catcher will not exceed 10{sup 7} ions per second. A charge breeder based on an Electron Beam Ion Source (EBIS) has significant advantages over the ECR option for ion beam intensities up to about 10{sup 9} ions per second, providing 3-4 times higher efficiency and significantly better purity of highly charged radioactive ion beams for further acceleration. The proposed EBIS project for CARIBU will heavily utilize state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory. This will allow us to reduce both the project cost and timescale, simultaneously insuring reliable technical realization of the cutting-edge technology. Several parameters of the CARIBU EBIS charge breeder (EBIS-CB) will be relaxed with respect to the BNL EBIS in favor of higher reliability and lower cost. Technical performance of the CARIBU charge breeder will not suffer from such a relaxation and will provide high efficiency for a whole range of radioactive ion beams. The goal of this paper is to present the initial design of the EBIS charge breeder for radioactive ion beams at ATLAS.

  16. Effect of O{sub 2}{sup +}, H{sub 2}{sup +}+ O{sub 2}{sup +}, and N{sub 2}{sup +}+ O{sub 2}{sup +} ion-beam irradiation on the field emission properties of carbon nanotubes

    SciTech Connect

    Acuna, J. J. S.; Alvarez, F.; Escobar, M.; Goyanes, S. N.; Candal, R. J.; Zanatta, A. R.

    2011-06-01

    The effect of O{sub 2}{sup +}, H{sub 2}{sup +}+ O{sub 2}{sup +}, and N{sub 2}{sup +}+ O{sub 2}{sup +} ion-beam irradiation of carbon nanotubes (CNTs) films on the chemical and electronic properties of the material is reported. The CNTs were grown by the chemical vapor deposition technique (CVD) on silicon TiN coated substrates previously decorated with Ni particles. The Ni decoration and TiN coating were successively deposited by ion-beam assisted deposition (IBAD) and afterwards the nanotubes were grown. The whole deposition procedure was performed in situ as well as the study of the effect of ion-beam irradiation on the CNTs by x-ray photoelectron spectroscopy (XPS). Raman scattering, field-effect emission gun scanning electron microscopy (FEG-SEM), and field emission (FE) measurements were performed ex situ. The experimental data show that: (a) the presence of either H{sub 2}{sup +} or N{sub 2}{sup +} ions in the irradiation beam determines the oxygen concentration remaining in the samples as well as the studied structural characteristics; (b) due to the experimental conditions used in the study, no morphological changes have been observed after irradiation of the CNTs; (c) the FE experiments indicate that the electron emission from the CNTs follows the Fowler-Nordheim model, and it is dependent on the oxygen concentration remaining in the samples; and (d) in association with FE results, the XPS data suggest that the formation of terminal quinone groups decreases the CNTs work function of the material.

  17. Overview of Light-Ion Beam Therapy

    SciTech Connect

    Chu, William T.

    2006-03-16

    compared to those in conventional (photon) treatments. Wilson wrote his personal account of this pioneering work in 1997. In 1954 Cornelius Tobias and John Lawrence at the Radiation Laboratory (former E.O. Lawrence Berkeley National Laboratory) of the University of California, Berkeley performed the first therapeutic exposure of human patients to hadron (deuteron and helium ion) beams at the 184-Inch Synchrocyclotron. By 1984, or 30 years after the first proton treatment at Berkeley, programs of proton radiation treatments had opened at: University of Uppsala, Sweden, 1957; the Massachusetts General Hospital-Harvard Cyclotron Laboratory (MGH/HCL), USA, 1961; Dubna (1967), Moscow (1969) and St Petersburg (1975) in Russia; Chiba (1979) and Tsukuba (1983) in Japan; and Villigen, Switzerland, 1984. These centers used the accelerators originally constructed for nuclear physics research. The experience at these centers has confirmed the efficacy of protons and light ions in increasing the tumor dose relative to normal tissue dose, with significant improvements in local control and patient survival for several tumor sites. M.R. Raju reviewed the early clinical studies. In 1990, the Loma Linda University Medical Center in California heralded in the age of dedicated medical accelerators when it commissioned its proton therapy facility with a 250-MeV synchrotron. Since then there has been a relatively rapid increase in the number of hospital-based proton treatment centers around the world, and by 2006 there are more than a dozen commercially-built facilities in use, five new facilities under construction, and more in planning stages. In the 1950s larger synchrotrons were built in the GeV region at Brookhaven (3-GeV Cosmotron) and at Berkeley (6-GeV Bevatron), and today most of the world's largest accelerators are synchrotrons. With advances in accelerator design in the early 1970s, synchrotrons at Berkeley and Princeton accelerated ions with atomic numbers between 6 and 18, at

  18. Surface Modification Energized by Focused Ion Beam: The Influence of Etch Rates & Aspect Ratio on Ripple Wavelengths.

    SciTech Connect

    MoberlyChan, W J

    2006-11-15

    Ion beams have been used to modify surface topography, producing nanometer-scale modulations (and even subnanometer ripples in this work) that have potential uses ranging from designing self-assembly structures, to controlling stiction of micromachined surfaces, to providing imprint templates for patterned media. Modern computer-controlled Focused Ion Beam tools enable alternating submicron patterned zones of such ion-eroded surfaces, as well as dramatically increasing the rate of ion beam processing. The DualBeam FIB/SEM also expedites process development while minimizing the use of materials that may be precious (Diamond) and/or produce hazardous byproducts (Beryllium). A FIB engineer can prototype a 3-by-3-by-3 matrix of variables in tens of minutes and consume as little as zeptoliters of material; whereas traditional ion beam processing would require tens of days and tens of precious wafers. Saturation wavelengths have been reported for ripples on materials such as single crystal silicon or diamond ({approx}200nm); however this work achieves wavelengths >400nm on natural diamond. Conversely, Be can provide a stable and ordered 2-dimensional array of <40nm periodicity; and ripples <0.4nm are also fabricated on carbon surfaces and quantified by HR-TEM and electron diffraction. Rippling is a function of material, ion beam, and angle; but is also controlled by chemical environment, redeposition, and aspect ratio. Ideally a material exhibits a constant yield (atoms sputtered off per incident ion); however, pragmatic FIB processes, coupled with the direct metrological feedback in a DualBeam tool, reveal etch rates do not remain constant for nanometer-scale processing. Control of rippling requires controlled metrology, and robust software tools are developed to enhance metrology. In situ monitoring of the influence of aspect ratio and redeposition at the micron scale correlates to the rippling fundamentals that occur at the nanometer scale and are controlled by the

  19. Shunting arc plasma source for pure carbon ion beam.

    PubMed

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  20. Polarization Studies in Fast-Ion Beam Spectroscopy

    SciTech Connect

    Trabert, E

    2001-12-20

    In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

  1. Experimental Studies of Ion Beam Neutralization: Preliminary Results

    SciTech Connect

    Ding, N.; Polansky, J.; Downey, R.; Wang, J.

    2011-05-20

    A testing platform is designed to study ion beam neutralization in the mesothermal, collisionless region. In the experimental setup, argon neutrals were ionized in a microwave cavity and accelerated by a plasma lens system which was biased to 2500 V above the system ground. Electrons were boiled off from two hot tungsten filaments to neutralize the ion beam. The plasma is diagnosed using Langmuir probe and Faraday probe. A 3-D traversing system and a complete data acquisition loop were developed to efficiently measure 3-D beam profile. Preliminary measurements of beam profiles are presented for different operating conditions.

  2. High-Quality Ion Beam Generation in Laser Plasma Interaction

    NASA Astrophysics Data System (ADS)

    Nagashima, Toshihiro; Takano, Masahiro; Izumiyzma, Takeshi; Barada, Daisuke; Kawata, Shigeo; Gu, Yan Jun; Kong, Qing; Xiao Wang, Ping; Ma, Yan Yun; Wang, Wei Min

    We focus on a control of generation of high-quality ion beam. In this study, near-critical density plasmas are employed and are illuminated by high intensity short laser pulses; we have successfully generated high-energy ions by multiple-stages acceleration. We performed particle-in-cell simulations in this paper. Near-critical density plasmas are employed at the proton source and also in the post acceleration. A beam bunching method is also proposed to control the ion beam length.

  3. Aerosol-Assisted Extraction of Silicon Nanoparticles from Wafer Slicing Waste for Lithium Ion Batteries

    PubMed Central

    Jang, Hee Dong; Kim, Hyekyoung; Chang, Hankwon; Kim, Jiwoong; Roh, Kee Min; Choi, Ji-Hyuk; Cho, Bong-Gyoo; Park, Eunjun; Kim, Hansu; Luo, Jiayan; Huang, Jiaxing

    2015-01-01

    A large amount of silicon debris particles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing. PMID:25819285

  4. Aerosol-assisted extraction of silicon nanoparticles from wafer slicing waste for lithium ion batteries.

    PubMed

    Jang, Hee Dong; Kim, Hyekyoung; Chang, Hankwon; Kim, Jiwoong; Roh, Kee Min; Choi, Ji-Hyuk; Cho, Bong-Gyoo; Park, Eunjun; Kim, Hansu; Luo, Jiayan; Huang, Jiaxing

    2015-01-01

    A large amount of silicon debris particles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing.

  5. Aerosol-assisted extraction of silicon nanoparticles from wafer slicing waste for lithium ion batteries.

    PubMed

    Jang, Hee Dong; Kim, Hyekyoung; Chang, Hankwon; Kim, Jiwoong; Roh, Kee Min; Choi, Ji-Hyuk; Cho, Bong-Gyoo; Park, Eunjun; Kim, Hansu; Luo, Jiayan; Huang, Jiaxing

    2015-01-01

    A large amount of silicon debris particles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing. PMID:25819285

  6. Aerosol-Assisted Extraction of Silicon Nanoparticles from Wafer Slicing Waste for Lithium Ion Batteries

    NASA Astrophysics Data System (ADS)

    Jang, Hee Dong; Kim, Hyekyoung; Chang, Hankwon; Kim, Jiwoong; Roh, Kee Min; Choi, Ji-Hyuk; Cho, Bong-Gyoo; Park, Eunjun; Kim, Hansu; Luo, Jiayan; Huang, Jiaxing

    2015-03-01

    A large amount of silicon debris particles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing.

  7. Ion Beam Transport Simulations for the 1.7 MV Tandem Accelerator at the Michigan Ion Beam Laboratory

    NASA Astrophysics Data System (ADS)

    Naab, F. U.; Toader, O. F.; Was, G. S.

    The Michigan Ion Beam Laboratory houses a 1.7 MV tandem accelerator. For many years this accelerator was configured to run with three ion sources: a TORoidal Volume Ion Source (TORVIS), a Duoplasmatron source and a Sputter source. In this article we describe an application we have created using the SIMION® code to simulate the trajectories of ion beams produced with these sources through the accelerator. The goal of this work is to have an analytical tool to understand the effect of each electromagnetic component on the ion trajectories. This effect is shown in detailed drawings. Each ion trajectory simulation starts at the aperture of the ion source and ends at the position of the target. Using these simulations, new accelerator operators or users quickly understand how the accelerator system works. Furthermore, these simulations allow analysis of modifications in the ion beam optics of the accelerator by adding, removing or replacing components or changing their relative positions.

  8. Schottky Barrier Catalysis Mechanism in Metal-Assisted Chemical Etching of Silicon.

    PubMed

    Lai, Ruby A; Hymel, Thomas M; Narasimhan, Vijay K; Cui, Yi

    2016-04-13

    Metal-assisted chemical etching (MACE) is a versatile anisotropic etch for silicon although its mechanism is not well understood. Here we propose that the Schottky junction formed between metal and silicon plays an essential role on the distribution of holes in silicon injected from hydrogen peroxide. The proposed mechanism can be used to explain the dependence of the etching kinetics on the doping level, doping type, crystallographic surface direction, and etchant solution composition. We used the doping dependence of the reaction to fabricate a novel etch stop for the reaction. PMID:27018712

  9. Inactivation of Human Cells by Heavy-ion Beams and Microdosimetric Estimates

    NASA Astrophysics Data System (ADS)

    Kase, Y.; Kanai, T.; Matsumoto, Y.; Furusawa, Y.; Sakama, M.; Asaba, T.

    In the field of heavy-ion therapy and space radiation protection the prediction of biological effects of heavy charged particles is an important problem In microdosimetry tissue-equivalent proportional counter TEPC has been often used to estimate the biological effect of ionizing radiations We measured the radiation quality of various ion beams using a spherical TEPC while the inactivation of in vitro human cells was investigated by colony assay The ion beams were provided by the Heavy-ion Medical Accelerator HIMAC in Chiba NIRS Japan The microdosimetric spectra of photon and proton- helium- carbon- neon- silicon- and iron-ions LET range from 0 5 to 880 keV micron were measured using a spherical walled TEPC with a tissue-equivalent diameter of 1 micron at various depths in a plastic phantom In the measurement of cell surviving curves human salivary grand HSG tumor cells were used as a human tumor cell line and GM05389 cells were used as a normal human fibroblast cell line The linear terms of linear quadratic model with a fixed quadratic term for surviving curves of each cell types were plotted as a function of the dose-mean lineal energy measured by the TEPC We found that these plots agreed with the microdosimetric kinetic MK model R B Hawkins 1994 for ion beams with a LET value of less than 450 keV micron as long as the saturation-corrected dose-mean lineal energy was used instead of dose-mean lineal energy with non-Poisson correction in the MK model Therefore in heavy ion therapy this microdosimetric estimate of the revised MK

  10. Quantitative carbon ion beam radiography and tomography with a flat-panel detector.

    PubMed

    Telsemeyer, Julia; Jäkel, Oliver; Martišíková, Mária

    2012-12-01

    High dose gradients are inherent to ion beam therapy. This results in high sensitivity to discrepancies between planned and delivered dose distributions. Therefore an accurate knowledge of the ion stopping power of the traversed tissue is critical. One proposed method to ensure high quality dose deposition is to measure the stopping power by ion radiography. Although the idea of imaging with highly energetic ions is more than forty years old, there is a lack of simple detectors suitable for this purpose. In this study the performance of an amorphous silicon flat-panel detector, originally designed for photon imaging, was investigated for quantitative carbon ion radiography and tomography. The flat-panel detector was exploited to measure the water equivalent thickness (WET) and water equivalent path length (WEPL) of a phantom at the Heidelberg Ion-Beam Therapy Center (HIT). To do so, the ambiguous correlation of detector signal to particle energy was overcome by active or passive variation of carbon ion beam energy and measurement of the signal-to-beam energy correlation. The active method enables one to determine the WET of the imaged object with an uncertainty of 0.5 mm WET. For tomographic WEPL measurements the passive method was exploited resulting in an accuracy of 0.01 WEPL. The developed imaging technique presents a method to measure the two-dimensional maps of WET and WEPL of phantoms with a simple and commercially available detector. High spatial resolution of 0.8 × 0.8 mm(2) is given by the detector design. In the future this powerful tool will be used to evaluate the performance of the treatment planning algorithm by studying WET uncertainties.

  11. Mechanical and tribological properties of ion beam-processed surfaces

    NASA Astrophysics Data System (ADS)

    Kodali, Padma

    A variety of surface modification and surface coating techniques are currently used in industry to modify the near-surface mechanical properties that influence the friction and wear behavior of metals, metallic alloys, ceramics, and polymers. Near-surface mechanical properties such as hardness and fracture toughness of a coating-substrate system can be tailored economically without changing the bulk properties of the system. The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) Investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation. (2) Characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation. (3) Developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. Wear mechanisms that occurred in implanted and unimplanted surfaces tested against AIS152100

  12. First atomic physics experiments with cooled stored ion beams at the Heidelberg heavy-ion ring TSR

    SciTech Connect

    Wolf, A.; Balykin, V.; Baumann, W.; Berger, J.; Bisoffi, G.; Blatt, P.; Blum, M.; Faulstich, A.; Friedrich, A.; Gerhard, M.; Geyer, C.; Grieser, M.; Grieser, R.; Habs, D.; Heyng, H.W.; Hochadel, B.; Holzer, B.; Huber, G.; Jaeschke, E.; Jung, M.; Karafillidis, A.; Kilgus, G.; Klein, R.; Kraemer, D.; Krause, P.; Krieg, M.; Kuehl, T.; Matl, K.; Mueller, A.; Music, M.; Neumann, R.; Neureither, G.; Ott, W.; Petrich, W.; Povh, B.; Repnow, R.; Schroeder, S.; Schuch, R.; Schwalm, D.; Sigray, P.; Steck, M.; Stokstad, R.; Szmola, E.; Wagner, M.; Wanner, B.; Welti, K.; Zwickler, S. Max-Planck-Institut fuer Kernphysik, Heidelberg Manne Siegbahn Institute , Stockholm Institut fuer Kernphysik, Universitaet Giessen, Institut fuer Physik, Universitaet Mainz Gesellschaft fuer Schwerionenforschung , Darmstadt (Fed

    1990-06-01

    An overview of atomic physics experiments at the heavy ion Test Storage Ring (TSR) is given. Highly charged ions up to fully stripped silicon have been stored at energies between 4 and 12 MeV/u. The enhancement of the beam intensity by stacking, the beam lifetime, and electron cooling of these ion beams are discussed. Radiative and state-selective dielectronic recombination rates of hydrogen-like oxygen ions with free electrons from the electron cooler were measured. Beam noise spectra are being investigated with regard to collective effects caused by the Coulomb interaction in the cold ion beams. Resonance fluorescence from stored single-charged ions was observed using tunable narrow-band lasers. First indications of laser cooling in a storage ring were seen.

  13. Ultrahigh vacuum focused ion beam micromill and articles therefrom

    DOEpatents

    Lamartine, B.C.; Stutz, R.A.

    1998-02-24

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

  14. Ultrahigh vacuum focused ion beam micromill and articles therefrom

    DOEpatents

    Lamartine, Bruce C.; Stutz, Roger A.

    1998-01-01

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

  15. ECR plasma source for heavy ion beam charge neutralization

    SciTech Connect

    Efthimion, P.C.; Gilson, E.; Grisham, L.; Kolchin, P.; Davidson, E.C.; Yu, S.S.; Logan, B.G.

    2002-05-01

    Highly ionized plasmas are being considered as a medium for charge neutralizing heavy ion beams in order to focus beyond the space-charge limit. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length {approx} 0.1-2 m would be suitable for achieving a high level of charge neutralization. An ECR source has been built at the Princeton Plasma Physics Laboratory (PPPL) to support a joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization with plasma. The ECR source operates at 13.6 MHz and with solenoid magnetic fields of 1-10 gauss. The goal is to operate the source at pressures {approx} 10{sup -6} Torr at full ionization. The initial operation of the source has been at pressures of 10{sup -4}-10{sup -1} Torr. Electron densities in the range of 10{sup 8}-10{sup 11} cm{sup -3} have been achieved. Low-pressure operation is important to reduce ion beam ionization. A cusp magnetic field has been installed to improve radial confinement and reduce the field strength on the beam axis. In addition, axial confinement is believed to be important to achieve lower-pressure operation. To further improve breakdown at low pressure, a weak electron source will be placed near the end of the ECR source.

  16. Drag of ballistic electrons by an ion beam

    SciTech Connect

    Gurevich, V. L.; Muradov, M. I.

    2015-12-15

    Drag of electrons of a one-dimensional ballistic nanowire by a nearby one-dimensional beam of ions is considered. We assume that the ion beam is represented by an ensemble of heavy ions of the same velocity V. The ratio of the drag current to the primary current carried by the ion beam is calculated. The drag current turns out to be a nonmonotonic function of velocity V. It has a sharp maximum for V near v{sub nF}/2, where n is the number of the uppermost electron miniband (channel) taking part in conduction and v{sub nF} is the corresponding Fermi velocity. This means that the phenomenon of ion beam drag can be used for investigation of the electron spectra of ballistic nanostructures. We note that whereas observation of the Coulomb drag between two parallel quantum wires may in general be complicated by phenomena such as tunneling and phonon drag, the Coulomb drag of electrons of a one-dimensional ballistic nanowire by an ion beam is free of such spurious effects.

  17. Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam

    SciTech Connect

    Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi

    2006-05-02

    This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

  18. Ion beam and plasma methods of producing diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Mirtich, Michael J.; Banks, Bruce A.

    1988-01-01

    A variety of plasma and ion beam techniques was employed to generate diamondlike carbon films. These methods included the use of RF sputtering, dc glow discharge, vacuum arc, plasma gun, ion beam sputtering, and both single and dual ion beam deposition. Since films were generated using a wide variety of techniques, the physico-chemical properties of these films varied considerably. In general, these films had characteristics that were desirable in a number of applications. For example, the films generated using both single and dual ion beam systems were evaluated for applications including power electronics as insulated gates and protective coatings on transmitting windows. These films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Nuclear reaction and combustion analysis indicated hydrogen to carbon ratios to be 1.00, which allowed the films to have good transmittance not only in the infrared, but also in the visible. Other evaluated properties of these films include band gap, resistivity, adherence, density, microhardness, and intrinsic stress. The results of these studies and those of the other techniques for depositing diamondlike carbon films are presented.

  19. Initial stages of the ion beam mixing process

    SciTech Connect

    Traverse, A.; Le Boite, M.G.; Nevot, L.; Pardo, B.; Corno, J.

    1987-12-07

    The grazing x-ray reflectometry technique, performed on irradiated periodic multilayers, was used to study the early stages of the ion beam mixing process. We present our first results, obtained on NiAu samples irradiated with He ions. The experimental fluence dependence of the effective diffusion coefficient is in good agreement with a calculation based on a purely ballistic process.

  20. Microfabricated Ion Beam Drivers for Magnetized Target Fusion

    NASA Astrophysics Data System (ADS)

    Persaud, Arun; Seidl, Peter; Ji, Qing; Ardanuc, Serhan; Miller, Joseph; Lal, Amit; Schenkel, Thomas

    2015-11-01

    Efficient, low-cost drivers are important for Magnetized Target Fusion (MTF). Ion beams offer a high degree of control to deliver the required mega joules of driver energy for MTF and they can be matched to several types of magnetized fuel targets, including compact toroids and solid targets. We describe an ion beam driver approach based on the MEQALAC concept (Multiple Electrostatic Quadrupole Array Linear Accelerator) with many beamlets in an array of micro-fabricated channels. The channels consist of a lattice of electrostatic quadrupoles (ESQ) for focusing and of radio-frequency (RF) electrodes for ion acceleration. Simulations with particle-in-cell and beam envelope codes predict >10x higher current densities compared to state-of-the-art ion accelerators. This increase results from dividing the total ion beam current up into many beamlets to control space charge forces. Focusing elements can be biased taking advantage of high breakdown electric fields in sub-mm structures formed using MEMS techniques (Micro-Electro-Mechanical Systems). We will present results on ion beam transport and acceleration in MEMS based beamlets. Acknowledgments: This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231.

  1. 21st International Conference on Ion Beam Analysis

    SciTech Connect

    Thevuthasan, Suntharampillai; Shutthanandan, V.; Wang, Yongqiang; Vizkelethy, Gyorgy; Rout, Bibhudutta

    2014-08-01

    This special issue of Nuclear Instruments and Methods in Physics Research B contains the proceedings of the 21st International Conference on Ion Beam Analysis (IBA – 2013). This conference was held in Marriott Waterfront in Seattle, Washington, USA during June 23–28, 2013.

  2. The Place of Ion Beams in Clinical Applications

    NASA Astrophysics Data System (ADS)

    Kim, Paul J.; Shih, Helen A.

    The place of ion beam therapy (IBT) in the clinic has evolved amid a dynamic environment of advancements on several fronts: tumor biology, diagnostic imaging, surgical and medical oncology, and radiotherapy treatment planning and delivery. This chapter will present generalized themes of the current place of IBT and current areas of investigation.

  3. Design and Implementation of Clinical Trials of Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Cox, James D.

    Design and implementation of clinical trials are complex even when those trials involve established technologies. Ion beam therapy (IBT) imposes additional requirements including sufficient institutional experience using ions for treatment, credentialing of institutions, formulating hypotheses of interest to investigators and to patients, and securing funding from national and private agencies. The effort, though, is very important to the future of radiation oncology.

  4. Models of self-pinched ion beam transport

    SciTech Connect

    Ottinger, P.F.; Rose, D.V. |; Welch, D.R.; Olson, C.L.

    1998-12-31

    Ion-beam-driven inertial confinement fusion (ICF) requires the efficient transport of intense, focused ion beams over distances of many meters to an ICF target. The self-pinch transport (SPT) scheme utilizes the incomplete current neutralization of an ion beam propagating in a low pressure background gas to radially confine the beam. Experiments and theoretical investigations are presently underway to assess the feasibility of this beam transport mechanism. Simulations of SPT are being carried out using the 3-D hybrid particle-in-cell code, IPROP. For this work, an intense ion beam is injected into different background gas pressures of argon and helium in order to determine the optimum gas pressure for SPT. In addition, simulations will be carried out that examine the effect on beam confinement of changing the ratio of the beam injection radius to the gas chamber wall radius, using different beam injection angles, and changing the beam current rise time. Along with the PIC simulations, several analytic models are being investigated and further developed for understanding the important physics of SPT and scaling for various applications. Available results are presented.

  5. Spin Observables in Reactions with Radioactive Ion Beams

    SciTech Connect

    Galindo-Uribarri, Alfredo {nmn}; Urrego Blanco, Juan Pablo

    2007-01-01

    Polarization observables in nuclear reactions with exotic nuclei will provide important information concerning structural properties of nuclei and reaction mechanisms. We are currently engaged in exploring the use of polarization observables with radioactive ion beams and in the development of a polarized cryogenic target.

  6. High resolution energy analyzer for broad ion beam characterization

    SciTech Connect

    Kanarov, V.; Hayes, A.; Yevtukhov, R.; Siegfried, D.; Sferlazzo, P.

    2008-09-15

    Characterization of the ion energy distribution function (IEDF) of low energy high current density ion beams by conventional retarding field and deflection type energy analyzers is limited due to finite ion beam emittance and beam space charge spreading inside the analyzer. These deficiencies are, to a large extent, overcome with the recent development of the variable-focusing retarding field energy analyzer (RFEA), which has a cylindrical focusing electrode preceding the planar retarding grid. The principal concept of this analyzer is conversion of a divergent charged particle beam into a quasiparallel beam before analyzing it by the planar retarding field. This allows analysis of the beam particle total kinetic energy distribution with greatly improved energy resolution. Whereas this concept was first applied to analyze 5-10 keV pulsed electron beams, the present authors have adapted it to analyze the energy distribution of a low energy ({<=}1 KeV) broad ion beam. In this paper we describe the RFEA design, which was modified from the original, mainly as required by the specifics of broad ion beam energy analysis, and the device experimental characterization and modeling results. Among the modifications, an orifice electrode placed in front of the RFEA provides better spatial resolution of the broad ion beam ion optics emission region and reduces the beam plasma density in the vicinity of analyzer entry. An electron repeller grid placed in front of the RFEA collector was found critical for suppressing secondary electrons, both those incoming to the collector and those released from its surface, and improved energy spectrum measurement repeatability and accuracy. The use of finer mesh single- and double-grid retarding structures reduces the retarding grid lens effect and improves the analyzer energy resolution and accuracy of the measured spectrum mean energy. However, additional analyzer component and configuration improvements did not further change the analyzed

  7. Plasma ion sources and ion beam technology inmicrofabrications

    SciTech Connect

    Ji, Lili

    2007-01-01

    For over decades, focused ion beam (FIB) has been playing a very important role in microscale technology and research, among which, semiconductor microfabrication is one of its biggest application area. As the dimensions of IC devices are scaled down, it has shown the need for new ion beam tools and new approaches to the fabrication of small-scale devices. In the meanwhile, nanotechnology has also deeply involved in material science research and bioresearch in recent years. The conventional FIB systems which utilize liquid gallium ion sources to achieve nanometer scale resolution can no longer meet the various requirements raised from such a wide application area such as low contamination, high throughput and so on. The drive towards controlling materials properties at nanometer length scales relies on the availability of efficient tools. In this thesis, three novel ion beam tools have been developed and investigated as the alternatives for the conventional FIB systems in some particular applications. An integrated focused ion beam (FIB) and scanning electron microscope (SEM) system has been developed for direct doping or surface modification. This new instrument employs a mini-RF driven plasma source to generate focused ion beam with various ion species, a FEI two-lens electron (2LE) column for SEM imaging, and a five-axis manipulator system for sample positioning. An all-electrostatic two-lens column has been designed to focus the ion beam extracted from the source. Based on the Munro ion optics simulation, beam spot sizes as small as 100 nm can be achieved at beam energies between 5 to 35 keV if a 5 μm-diameter extraction aperture is used. Smaller beam spot sizes can be obtained with smaller apertures at sacrifice of some beam current. The FEI 2LE column, which utilizes Schottky emission, electrostatic focusing optics, and stacked-disk column construction, can provide high-resolution (as small as 20 nm) imaging capability, with fairly long working distance (25

  8. Friction and Wear of Ion-Beam-Deposited Diamondlike Carbon on Chemical-Vapor-Deposited, Fine-Grain Diamond

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Wu, Richard L. C.; Lanter, William C.

    1996-01-01

    Friction and wear behavior of ion-beam-deposited diamondlike carbon (DLC) films coated on chemical-vapor-deposited (CVD), fine-grain diamond coatings were examined in ultrahigh vacuum, dry nitrogen, and humid air environments. The DLC films were produced by the direct impact of an ion beam (composed of a 3:17 mixture of Ar and CH4) at ion energies of 1500 and 700 eV and an RF power of 99 W. Sliding friction experiments were conducted with hemispherical CVD diamond pins sliding on four different carbon-base coating systems: DLC films on CVD diamond; DLC films on silicon; as-deposited, fine-grain CVD diamond; and carbon-ion-implanted, fine-grain CVD diamond on silicon. Results indicate that in ultrahigh vacuum the ion-beam-deposited DLC films on fine-grain CVD diamond (similar to the ion-implanted CVD diamond) greatly decrease both the friction and wear of fine-grain CVD diamond films and provide solid lubrication. In dry nitrogen and in humid air, ion-beam-deposited DLC films on fine-grain CVD diamond films also had a low steady-state coefficient of friction and a low wear rate. These tribological performance benefits, coupled with a wider range of coating thicknesses, led to longer endurance life and improved wear resistance for the DLC deposited on fine-grain CVD diamond in comparison to the ion-implanted diamond films. Thus, DLC deposited on fine-grain CVD diamond films can be an effective wear-resistant, lubricating coating regardless of environment.

  9. Expansion of the radioactive ion beam program at Argonne

    NASA Astrophysics Data System (ADS)

    Clark, J. A.

    2011-01-01

    The Argonne Tandem Linear Accelerator System (ATLAS) at Argonne National Laboratory (ANL) provides a wide range of stable ion beams and radioactive beams which have contributed to our understanding of nuclear structure and reactions. Until now, most radioactive ion beams at ATLAS were produced in flight using light-ion reactions such as (p, n), (d, n), (d, p), (d,3He), and (3He,n). Within the next few months, the radioactive ion beam program at ATLAS will acquire much extended, new capabilities with the commissioning of a new facility: the CAlifornium Rare Isotope Breeder Upgrade (CARIBU). CARIBU will supply ion beams of 252Cf fission fragments, which are thermalized in a gas catcher. The singly- and doubly-charged ions extracted from the gas catcher will be mass-separated and either delivered to a low-energy experimental area, or charge bred with a modified ECR source and subsequently reaccelerated by the ATLAS facility. Properties of hundreds of these neutron-rich nuclides will be investigated using ion traps, decay stations, the newly commissioned HELical Orbit Spectrometer (HELIOS), and other available experimental equipment such as Gammasphere and the FMA. HELIOS was constructed to take advantage of rare ion beams, such as those provided by CARIBU, through light-ion transfer reactions in inverse kinematics, and represents a new approach to the study of direct reactions in inverse kinematics which avoids kinematic broadening. Experiments are currently being conducted with HELIOS, and first results with the d(28Si,p) and d(12B,p) reactions have shown excellent energy resolution.

  10. Ion-Beam-Induced Chemical Mixing at a Nanocrystalline CeO2 Si Interface

    SciTech Connect

    Edmondson, Dr. Philip; Young, Neil P.; Parish, Chad M; Moll, Sandra; Namavar, Fereydoon; Weber, William J; Zhang, Yanwen

    2013-01-01

    Thin films of nanocrystalline ceria deposited onto a silicon substrate have been irradiated with 3 MeV Au+ ions to a total dose of 34 displacements per atom to examine the film/substrate interfacial response upon displacement damage. Under irradiation, a band of contrast is observed to form that grows under further irradiation. Scanning and high-resolution transmission electron microscopy imaging and analysis suggest that this band of contrast is a cerium silicate phase with an approximate Ce:Si:O composition ratio of 1:1:3 in an amorphous nature. The slightly nonstoichiometric composition arises due to the loss of mobile oxygen within the cerium silicate phase under the current irradiation condition. This nonequilibrium phase is formed as a direct result of ion-beam-induced chemical mixing caused by ballistic collisions between the incoming ion and the lattice atoms. This may hold promise in ion beam engineering of cerium silicates for microelectronic applications e.g., the fabrication of blue LEDs.

  11. Development and Commissioning of an External Beam Facility in the Union College Ion Beam Analysis Laboratory

    NASA Astrophysics Data System (ADS)

    Yoskowitz, Joshua; Clark, Morgan; Labrake, Scott; Vineyard, Michael

    2015-10-01

    We have developed an external beam facility for the 1.1-MV tandem Pelletron accelerator in the Union College Ion Beam Analysis Laboratory. The beam is extracted from an aluminum pipe through a 1 / 4 ' ' diameter window with a 7.5- μm thick Kapton foil. This external beam facility allows us to perform ion beam analysis on samples that cannot be put under vacuum, including wet samples and samples too large to fit into the scattering chamber. We have commissioned the new facility by performing proton induced X-ray emission (PIXE) analysis of several samples of environmental interest. These include samples of artificial turf, running tracks, and a human tooth with an amalgam filling. A 1.7-MeV external proton beam was incident on the samples positioned 2 cm from the window. The resulting X-rays were measured using a silicon drift detector and were analyzed using GUPIX software to determine the concentrations of elements in the samples. The results on the human tooth indicate that while significant concentrations of Hg, Ag, and Sn are present in the amalgam filling, only trace amounts of Hg appear to have leached into the tooth. The artificial turf and running tracks show rather large concentrations of a broad range of elements and trace amounts of Pb in the turf infill.

  12. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams.

    PubMed

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E; Lacasta, Carlos; Oliver, Josep F; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-21

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing (22)Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy. PMID:27352107

  13. Thermal effects on the Ga+ ion beam induced structural modification of a-SiC:H

    NASA Astrophysics Data System (ADS)

    Tsvetkova, T.; Wright, C. D.; Craciun, M. F.; Bischoff, L.; Angelov, O.; Dimova-Malinovska, D.

    2012-12-01

    The effects of implantation temperature and post-implantation thermal annealing on the Ga+ ion beam induced optical contrast formation in hydrogenated silicon-carbon alloy (a-SiC:H) films and underlying structural modifications have been studied. The optical contrast formed (between implanted and unimplanted regions of the film material) has been made use of in the form of optical pattern formation by computer-operated Ga+-focused ion beam. Possible applications of this effect in the area of submicron lithography and high-density optical data storage have been suggested with regard to the most widely spread focused micro-beam systems based on Ga+ liquid metal ion sources. The implanted samples were structurally analysed using vibrational spectroscopies, like Raman and infra-red (IR) spectroscopy, to define optimum implantation conditions. The precise role of implantation temperature effects, i.e. the target temperature during Ga+ ion irradiation, on the structural modification obtainable has been therefore a key part of this study. Appropriate post-implantation annealing treatments were also studied, since these are expected to offer further benefits in reducing the required ion dose and enhancing the optical contrast, thus increasing the cost-effectiveness of the method.

  14. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    NASA Astrophysics Data System (ADS)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  15. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    NASA Astrophysics Data System (ADS)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3–5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  16. MeV ion beam lithography of biocompatible halogenated Parylenes using aperture masks

    NASA Astrophysics Data System (ADS)

    Whitlow, Harry J.; Norarat, Rattanaporn; Roccio, Marta; Jeanneret, Patrick; Guibert, Edouard; Bergamin, Maxime; Fiorucci, Gianni; Homsy, Alexandra; Laux, Edith; Keppner, Herbert; Senn, Pascal

    2015-07-01

    Parylenes are poly(p-xylylene) polymers that are widely used as moisture barriers and in biomedicine because of their good biocompatibility. We have investigated MeV ion beam lithography using 16O+ ions for writing defined patterns in Parylene-C, which is evaluated as a coating material for the Cochlear Implant (CI) electrode array, a neuroprosthesis to treat some forms of deafness. Parylene-C and -F on silicon and glass substrates as well as 50 μm thick PTFE were irradiated to different fluences (1 ×1013 - 1 ×1016 1 MeV 16O+ ions cm-2) through aperture masks under high vacuum and a low pressure (<10-3 mbar) oxygen atmosphere. Biocompatibility of the irradiated and unirradiated surfaces was tested by cell-counting to determine the proliferation of murine spiral ganglion cells. The results reveal that an oxygen ion beam can be used to pattern Parylene-C and -F without using a liquid solvent developer in a similar manner to PTFE but with a ∼25× smaller removal rate. Biocompatibility tests showed no difference in cell adhesion between irradiated and unirradiated areas or ion fluence dependence. Coating the Parylene surface with an adhesion-promoting protein mixture had a much greater effect on cell proliferation.

  17. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams.

    PubMed

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E; Lacasta, Carlos; Oliver, Josep F; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-21

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing (22)Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  18. Progress in bright ion beams for industry, medicine and fusion at LBNL

    SciTech Connect

    Kwan, Joe W.

    2002-05-31

    Recent progresses at LBNL in developing ion beams for industry, radiation therapy and inertial fusion applications were discussed. The highlights include ion beam lithography, boron neutron capture therapy (BNCT), and heavy ion fusion (HIF) drivers using multiple linacs.

  19. Properties of ion beam deposited Pb/sub 1-//sub x/La/sub x/(Zr/sub y/Ti/sub z/)/sub 1-//sub x//sub /4/O/sub 3/

    SciTech Connect

    Boyer, L.L.; Wu, A.Y.; Metzger, G.W.; McNeil, J.R.

    1989-05-01

    We have recently investigated ion beam sputtering and ion assisted deposition of Pb/sub 1-//sub x/La/sub x/(Zr/sub y/Ti/sub z/)/sub 1-//sub x//sub /4/O/sub 3/ (PLZT). Ion beam sputtered PLZT films display strong second-harmonic generation. Good quality material has been deposited on substrates of Si, Si with a buffer layer of SiO/sub 2/ , and fused silica. The surface morphology of ion beam sputtered PLZT is of very high quality.

  20. Incorporation and redistribution of impurities into silicon nanowires during metal-particle-assisted growth.

    PubMed

    Chen, Wanghua; Yu, Linwei; Misra, Soumyadeep; Fan, Zheng; Pareige, Philippe; Patriarche, Gilles; Bouchoule, Sophie; Roca i Cabarrocas, Pere

    2014-06-12

    The incorporation of metal atoms into silicon nanowires during metal-particle-assisted growth is a critical issue for various nanowire-based applications. Here we have been able to access directly the incorporation and redistribution of metal atoms into silicon nanowires produced by two different processes at growth rates ranging from 3 to 40 nm s(-1), by using laser-assisted atom probe tomography and scanning transmission electron microscopy. We find that the concentration of metal impurities in crystalline silicon nanowires increases with the growth rate and can reach a level of two orders of magnitude higher than that in their equilibrium solubility. Moreover, we demonstrate that the impurities are first incorporated into nanowire volume and then segregate at defects such as the twin planes. A dimer-atom-insertion kinetic model is proposed to account for the impurity incorporation into nanowires.

  1. New advancements in focused ion beam repair of alternating phase-shift masks

    NASA Astrophysics Data System (ADS)

    Lessing, Joshua; Robinson, Tod; Brannen, Rey A.; Morrison, Troy B.; Holtermann, Theresa

    2003-08-01

    As advanced photolithography extends the ability to print feature sizes below the 100 nm technology node, various reticle enhancement techniques (RET) are being employed to improve resolution. An example of RET is the alternating phase shift mask (APSM), which currently challenges the ability of conventional repair techniques to repair even the most basic reticle defect. The phase shifting quartz bump is one defect type critical to the performance of APSM technology masks. These defects on the APSM reticle are caused by imperfections in the resist image during processing, resulting in a localized under or over etch of the quartz substrate. The integrated application of gas assisted etch (GAE), focused ion beam (FIB) reticle repair, and atomic force microscopy (AFM), provide a comprehensive solution for advanced reticle defect repair and characterization. Ion beam repair offers superior accuracy and precision for removal without significant damage to the underlying or adjacent quartz. The AFM technique provides quantitative measurement of 3D structures, including those associated with alternating phase shifters etched into quartz as well as embedded shifters. In the work presented in this paper, quartz bum defects were pre-scanned on an AFM tool and proprietary software algorithms were used to generate defect image and height map files for transfer to the FIB reticle repair tool via a network connection. The FIB tool then used these files to control selectively the ion dose during the corresponding quartz defect repair. A 193 nm APSM phase shift photomask with programmed defects in 400 nm line and space pattern was repaired using an FEI Stylus NanoProfilometer (SNP) and a FEI Accura 850 focus ion beam (FIB) tool. Using the APSM FIB repair method, the transmittance evaluated from 193 nm AIMS at the repair area was more than 90% without post-processing.

  2. Insights into gold-catalyzed plasma-assisted CVD growth of silicon nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Wanghua; Roca i Cabarrocas, Pere

    2016-07-01

    Understanding and controlling effectively the behavior of metal catalyst droplets during the Vapor-Liquid-Solid growth of nanowires are crucial for their applications. In this work, silicon nanowires are produced by plasma-assisted Chemical Vapor Deposition using gold as a catalyst. The influence of hydrogen plasma on nanowire growth is investigated experimentally and theoretically. Interestingly, in contrast to conventional chemical vapor deposition, the growth rate of silicon nanowires shows a decrease as a function of their diameters, which is consistent with the incorporation of silicon via sidewall diffusion. We show that Ostwald ripening of catalyst droplets during nanowire growth is inhibited in the presence of a hydrogen plasma. However, when the plasma is off, the diffusion of Au atoms on the nanowire sidewall can take place. Based on this observation, we have developed a convenient method to grow silicon nanotrees.

  3. Images of Complex Interactions of an Intense Ion Beam with Plasma Electrons

    SciTech Connect

    Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

    2004-08-03

    Ion beam propagation in a background plasma is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because plasma electrons move in strong electric and magnetic fields of the beam. Computer simulation images of plasma interaction with an intense ion beam pulse are presented.

  4. Polyelectrolyte multilayer-assisted fabrication of non-periodic silicon nanocolumn substrates for cellular interface applications

    NASA Astrophysics Data System (ADS)

    Lee, Seyeong; Kim, Dongyoon; Kim, Seong-Min; Kim, Jeong-Ah; Kim, Taesoo; Kim, Dong-Yu; Yoon, Myung-Han

    2015-08-01

    Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical silicon nanocolumn arrays were successfully fabricated on a wafer scale, while each nanocolumn geometric factor, such as the diameter, height, density, and spatial patterning, could be fully controlled in an independent manner. Finally, we demonstrate that our vertical silicon nanocolumn substrates support viable cell culture with minimal cell penetration and unhindered cell motility due to the blunt nanocolumn morphology. These results suggest that vertical silicon nanocolumn substrates may serve as a useful cellular interface platform for performing a statistically meaningful number of cellular experiments in the fields of biomolecular delivery, stem cell research, etc.Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical

  5. The mechanism of galvanic/metal-assisted etching of silicon

    NASA Astrophysics Data System (ADS)

    Kolasinski, Kurt W.

    2014-08-01

    Metal-assisted etching is initiated by hole injection from an oxidant catalyzed by a metal nanoparticle or film on a Si surface. It is shown that the electronic structure of the metal/Si interface, i.e., band bending, is not conducive to diffusion of the injected hole away from the metal in the case of Ag or away from the metal/Si interface in the cases of Au, Pd, and Pt. Since holes do not diffuse away from the metals, the electric field resulting from charging of the metal after hole injection must instead be the cause of metal-assisted etching.

  6. Fracture Tests of Etched Components Using a Focused Ion Beam Machine

    NASA Technical Reports Server (NTRS)

    Kuhn, Jonathan, L.; Fettig, Rainer K.; Moseley, S. Harvey; Kutyrev, Alexander S.; Orloff, Jon; Powers, Edward I. (Technical Monitor)

    2000-01-01

    Many optical MEMS device designs involve large arrays of thin (0.5 to 1 micron components subjected to high stresses due to cyclic loading. These devices are fabricated from a variety of materials, and the properties strongly depend on size and processing. Our objective is to develop standard and convenient test methods that can be used to measure the properties of large numbers of witness samples, for every device we build. In this work we explore a variety of fracture test configurations for 0.5 micron thick silicon nitride membranes machined using the Reactive Ion Etching (RIE) process. Testing was completed using an FEI 620 dual focused ion beam milling machine. Static loads were applied using a probe. and dynamic loads were applied through a piezo-electric stack mounted at the base of the probe. Results from the tests are presented and compared, and application for predicting fracture probability of large arrays of devices are considered.

  7. Microdosimetric measurements and estimation of human cell survival for heavy-ion beams.

    PubMed

    Kase, Yuki; Kanai, Tatsuaki; Matsumoto, Yoshitaka; Furusawa, Yoshiya; Okamoto, Hiroyuki; Asaba, Toru; Sakama, Makoto; Shinoda, Hiroshi

    2006-10-01

    The microdosimetric spectra for high-energy beams of photons and proton, helium, carbon, neon, silicon and iron ions (LET = 0.5-880 keV/microm) were measured with a spherical-walled tissue-equivalent proportional counter at various depths in a plastic phantom. Survival curves for human tumor cells were also obtained under the same conditions. Then the survival curves were compared with those estimated by a microdosimetric model based on the spectra and the biological parameters for each cell line. The estimated alpha terms of the liner-quadratic model with a fixed beta value reproduced the experimental results for cell irradiation for ion beams with LETs of less than 450 keV/microm, except in the region near the distal peak. PMID:17007551

  8. First demonstration of X-ray mirrors using focused ion beam

    NASA Astrophysics Data System (ADS)

    Numazawa, Masaki; Ezoe, Yuichiro; Ishikawa, Kumi; Ogawa, Tomohiro; Sato, Mayu; Nakamura, Kasumi; Takeuchi, Kazuma; Terada, Masaru; Ohashi, Takaya; Mitsuda, Kazuhisa; Kelley, Ron; Murata, Kaoru

    2016-06-01

    We report on novel X-ray mirrors fabricated with a focused ion beam for future astronomical missions. We fabricated a test sample from a silicon wafer by forming six slits whose sidewalls were used as X-ray reflection surfaces. The six slits were designed with a size of 25 × 300 × 170 µm3 and with different inclination angles of 0 and ±1°. We examined X-ray reflection using three slits with different inclination angles at Al Kα 1.49 keV. Consequently, we demonstrated X-ray reflection from all the three slits. All the sidewalls have multiangular components with a microroughness of ˜1 nm rms. ˜30-45% of the total surface area is effective for X-ray reflection. We confirmed that the inclination angles are consistent with the designed values.

  9. Simulation of ion beam injection and extraction in an EBIS

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Kim, J. S.

    2016-02-01

    An example simulation of Au+ charge breeding using FAR-TECH's integrated EBIS (electron beam ion source) modeling toolset is presented with the emphasis on ion beam injection and extraction. The trajectories of injected ions are calculated with PBGUNS (particle beam gun simulation) self-consistently by including the space charges from both ions and electrons. The ion beam, starting with initial conditions within the 100% acceptance of the electron beam, is then tracked by EBIS-PIC (particle-in-cell EBIS simulation code). In the trap, the evolution of the ion charge state distribution is estimated by charge state estimator. The extraction of charge bred ions is simulated with PBGUNS. The simulations of the ion injections show significant ion space charge effects on beam capture efficiency and the ionization efficiency.

  10. Diagnostics for ion beam driven high energy density physics experiments

    SciTech Connect

    Bieniosek, F. M.; Henestroza, E.; Lidia, S.; Ni, P. A.

    2010-10-15

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K{sup +} beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  11. Diagnostics for ion beam driven high energy density physics experiments.

    PubMed

    Bieniosek, F M; Henestroza, E; Lidia, S; Ni, P A

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K(+) beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  12. Computers and the design of ion beam optical systems

    NASA Astrophysics Data System (ADS)

    White, Nicholas R.

    Advances in microcomputers have made it possible to maintain a library of advanced ion optical programs which can be used on inexpensive computer hardware, which are suitable for the design of a variety of ion beam systems including ion implanters, giving excellent results. This paper describes in outline the steps typically involved in designing a complete ion beam system for materials modification applications. Two computer programs are described which, although based largely on algorithms which have been in use for many years, make possible detailed beam optical calculations using microcomputers, specifically the IBM PC. OPTICIAN is an interactive first-order program for tracing beam envelopes through complex optical systems. SORCERY is a versatile program for solving Laplace's and Poisson's equations by finite difference methods using successive over-relaxation. Ion and electron trajectories can be traced through these potential fields, and plots of beam emittance obtained.

  13. Application of HOPG and CVD graphene as ion beam detectors

    NASA Astrophysics Data System (ADS)

    Kozubek, Roland; Ochedowski, Oliver; Zagoranskiy, Igor; Karlušić, Marko; Schleberger, Marika

    2014-12-01

    Highly ordered pyrolytic graphite and graphene created via chemical vapor deposition have been irradiated with high energetic I6+ ions. By Raman mapping an increase of the ID /IG ratio could be identified which arises from the ion induced defects. This ratio grows with increasing fluence. Using this as a tool, HOPG and graphene can be utilized to determine the ion beam spot size and its homogeneity. Both systems seem to be suitable for size determination of the spot. But due to the much higher sensitivity of graphene to ion irradiation, more detailed information regarding the homogeneity of the beam can only be derived using this 2D system. By comparison of both systems we conclude, that CVD graphene is more suitable as an ion beam detector, while HOPG is sufficient for a rough spot size analysis.

  14. Ion-beam-induced deoxyribose nucleic acid transfer

    NASA Astrophysics Data System (ADS)

    Anuntalabhochai, S.; Chandej, R.; Phanchaisri, B.; Yu, L. D.; Vilaithong, T.; Brown, I. G.

    2001-04-01

    We report our observations of the interaction of energetic ions with bacterial cells, inducing direct deoxyribose nucleic acid (DNA) transfer into Escherichia coli (E. coli). Argon- and nitrogen-ion beams were used to bombard the bacteria E. coli in a vacuum with energy of 26 keV and fluence in the range 0.5-4×1015 ions/cm2. Three DNA plasmids, pGEM2, pGEM-T easy, and pGFP, carrying different marker genes, were subsequently transferred (separately) into the appropriately ion-bombarded bacteria and successfully expressed. The results of this study indicate that ion beams with an energy such that the ion range is approximately equal to the cell envelope thickness, at a certain range of fluence, are able to generate pathways for macromolecule transfer through the envelope without irreversible damage.

  15. Focused-ion-beam-induced deposition of superconducting nanowires

    NASA Astrophysics Data System (ADS)

    Sadki, E. S.; Ooi, S.; Hirata, K.

    2004-12-01

    Superconducting nanowires, with a critical temperature of 5.2K, have been synthesized using an ion-beam-induced deposition, with a gallium focused ion beam and tungsten carboxyl, W(CO)6, as precursor. The films are amorphous, with atomic concentrations of about 40%, 40%, and 20% for W, C, and Ga, respectively, 0K values of the upper critical field and coherence length of 9.5T and 5.9nm, respectively, are deduced from the resistivity data at different applied magnetic fields. The critical current density is Jc=1.5×105A /cm2 at 3K. This technique can be used as a template-free fabrication method for superconducting devices.

  16. Simulating Intense Ion Beams for Inertial Fusion Energy

    SciTech Connect

    Friedman, A

    2001-02-20

    The Heavy Ion Fusion (HIF) program's goal is the development of the body of knowledge needed for Inertial Fusion Energy (IFE) to realize its promise. The intense ion beams that will drive HIF targets are nonneutral plasmas and exhibit collective, nonlinear dynamics which must be understood using the kinetic models of plasma physics. This beam physics is both rich and subtle: a wide range in spatial and temporal scales is involved, and effects associated with both instabilities and non-ideal processes must be understood. Ion beams have a ''long memory'', and initialization of a beam at mid-system with an idealized particle distribution introduces uncertainties; thus, it will be crucial to develop, and to extensively use, an integrated and detailed ''source-to-target'' HIF beam simulation capability. We begin with an overview of major issues.

  17. Simulating Intense Ion Beams for Inertial Fusion Energy

    SciTech Connect

    Friedman, A.

    2001-02-20

    The Heavy Ion Fusion (HIF) program's goal is the development of the body of knowledge needed for Inertial Fusion Energy (IFE) to realize its promise. The intense ion beams that will drive HIF targets are rzonneutral plasmas and exhibit collective, nonlinear dynamics which must be understood using the kinetic models of plasma physics. This beam physics is both rich and subtle: a wide range in spatial and temporal scales is involved, and effects associated with both instabilities and non-ideal processes must be understood. Ion beams have a ''long memory,'' and initialization of a beam at mid-system with an idealized particle distribution introduces uncertainties; thus, it will be crucial to develop, and to extensively use, an integrated and detailed ''source-to-target'' HIF beam simulation capability. We begin with an overview of major issues.

  18. Ion-beam-induced topography and surface diffusion

    NASA Technical Reports Server (NTRS)

    Robinson, R. S.; Rossnagel, S. M.

    1982-01-01

    It is pointed out that the development of surface topography along with enhanced surface and bulk diffusion processes accompanying ion bombardment have generated growing interest among users of ion beams and plasmas for thin film or material processing. Interest in these processes stems both from attempts to generate topographic changes for specific studies or applications and from the need to suppress or control undesirable changes. The present investigation provides a summary of the current status of impurity-induced texturing, with emphasis on recent developments. Particular attention is given to the texturing accompanying deposition of an impurity material onto a solid surface while simultaneously etching the surface with an ion beam. A description of experimental considerations is provided, and a thermal-diffusion model is discussed along with the development of sputter cones, and aspects of impact-enhanced surface diffusion.

  19. Ion Beam Analysis of Targets Used in Controlatron Neutron Generators

    SciTech Connect

    Banks, James C.; Doyle, Barney L.; Walla, Lisa A.; Walsh, David S.

    2009-03-10

    Controlatron neutron generators are used for testing neutron detection systems at Sandia National Laboratories. To provide for increased tube lifetimes for the moderate neutron flux output of these generators, metal hydride (ZrT{sub 2}) target fabrication processes have been developed. To provide for manufacturing quality control of these targets, ion beam analysis techniques are used to determine film composition. The load ratios (i.e. T/Zr concentration ratios) of ZrT{sub 2} Controlatron neutron generator targets have been successfully measured by simultaneously acquiring RBS and ERD data using a He{sup ++} beam energy of 10 MeV. Several targets were measured and the film thicknesses obtained from RBS measurements agreed within {+-}2% with Dektak profilometer measurements. The target fabrication process and ion beam analysis techniques will be presented.

  20. Effects on focused ion beam irradiation on MOS transistors

    SciTech Connect

    Campbell, A.N.; Peterson, K.A.; Fleetwood, D.M.; Soden, J.M.

    1997-04-01

    The effects of irradiation from a focused ion beam (FIB) system on MOS transistors are reported systematically for the first time. Three MOS transistor technologies, with 0.5, 1, and 3 {mu}m minimum feature sizes and with gate oxide thicknesses ranging from 11 to 50 nm, were analyzed. Significant shifts in transistor parameters (such as threshold voltage, transconductance, and mobility) were observed following irradiation with a 30 keV Ga{sup +} focused ion beam with ion doses varying by over 5 orders of magnitude. The apparent damage mechanism (which involved the creation of interface traps, oxide trapped charge, or both) and extent of damage were different for each of the three technologies investigated.

  1. Nonlinear transient neutralization theory of ion beams with dissipation

    NASA Technical Reports Server (NTRS)

    Wilhelm, H. E.

    1975-01-01

    An analytical theory of nonlinear neutralization waves generated by injection of electrons from a grid in the direction of a homogeneous ion beam of uniform velocity and infinite extension is presented. The electrons are assumed to interact with the ions through the self-consistent space charge field and by strong collective interactions. The associated nonlinear boundary-value problem is solved in closed form by means of a von Mises transformation. It is shown that the electron gas moves into the ion space in the form of a discontinuous neutralization wave. This periodic wave structure is damped out by intercomponent momentum transfer, i.e., after a few relaxation lengths a quasi-neutral beam results. The relaxation scale in space agrees with neutralization experiments of rarefied ion beams, if the collective momentum transfer between the electron and ion streams is assumed to be of the Buneman type.

  2. The influence of stray magnetic fields on ion beam neutralization

    NASA Technical Reports Server (NTRS)

    Feng, Y.-C.; Wilbur, P. J.

    1982-01-01

    An experimental investigation is described of a comparison between the ion beam neutralization characteristics of a local neutralizer (within approximately 5 cm of the beam edge) and those associated with a distant one (approximately 1 meter away from the thruster). The influence of magnetic fields in the vicinity of the neutralizer cathode orifice which are either parallel or normal to the neutralizer axis is assessed. The plasma property profiles which reflect the influence of the magnetic fields are measured. The results suggest that magnetic fields at the region of a neutralizer cathode orifice influence its ability to couple to the ion beam. They reveal that there is a potential jump from the neutralizer cathode orifice to the plasma which exists close to the orifice. This potential drop is found to increase as the axial component of magnetic flux density increases. A magnetic field perpendicular to the neutralizer axis induces a potential rise a few centimeters downstream from the neutralizer cathode.

  3. Space Charge Neutralization in the ITER Negative Ion Beams

    SciTech Connect

    Surrey, Elizabeth

    2007-08-10

    A model of the space charge neutralization of negative ion beams, developed from the model due to Holmes, is applied to the ITER heating and diagnostic beams. The Holmes model assumed that the plasma electron temperature was derived from the stripped electrons. This is shown to be incorrect for the ITER beams and the plasma electron temperature is obtained from the average creation energy upon ionization. The model shows that both ITER beams will be fully space charge compensated in the drift distance between the accelerator and the neutralizer. Inside the neutralizer, the plasma over compensates the space charge to the extent that a significant focusing force is predicted. At a certain position in the neutraliser this force balances the defocusing force due to the ions' transverse energy. Under these conditions the beam distribution function can change from Gaussian to Bennett and evidence of such a distribution observed in a multi-aperture, neutralized negative ion beam is presented.

  4. Diagnostics for ion beam driven high energy density physics experiments.

    PubMed

    Bieniosek, F M; Henestroza, E; Lidia, S; Ni, P A

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K(+) beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II. PMID:21033977

  5. DIAGNOSTICS FOR ION BEAM DRIVEN HIGH ENERGY DENSITY PHYSICS EXPERIMENTS

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Lidia, S.; Ni, P.A.

    2010-01-04

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30-mA K{sup +} beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (VISAR), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  6. Ion beam mixing of titanium overlayers with hydroxyapaptite substrates

    SciTech Connect

    Levine, T.E.; Nastasi, M.; Alford, T.L.; Suchicital, C.; Russell, S.; Luptak, K.; Pizziconi, V.; Mayer, J.W.

    1995-01-01

    The mixing of titanium overlayers with hydroxyapatite (HA) substrates via ion irradiation has been demonstrated. Analysis via secondary ion mass spectroscopy (SIMS) indicates an interfacial broadening of titanium and calcium of the implanted sample compared to that of the unimplanted sample. Attendant to the observed ion beam mixing of titanium into the HA, the oxygen signal of the titanium overlayer increases as a result of ion irradiation. It is supposed that this change is evident of diffusion through the metal layer and possibly from titania formation at the free surface and perovskite formation at the film/substrate interface. This possibility is consistent with thermodynamic predictions. Additionally, the force required to separate the film from the substrate increased as a result of ion irradiation, validating the continued study of ion beam processing of Ti/HA systems towards the improvement of long term fixation of implant devices.

  7. Production of highly charged ion beams with SECRAL.

    PubMed

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

    2010-02-01

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

  8. A microsecond-pulsewidth, intense, light-ion beam accelerator

    SciTech Connect

    Rej, D.J.; Bartsch, R.R.; Davis, H.A.; Greenly, J.B.; Waganaar, W.J.

    1993-07-01

    A relatively long-pulsewidth (0.1-1 {mu}s) intense ion beam accelerator has been built for materials processing applications. An applied-B{sub r}, magnetically-insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2-MV, 300-kJ Marx generator. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse-shaping.

  9. Ion beam analysis of diffusion in heterogeneous materials

    NASA Astrophysics Data System (ADS)

    Clough, A. S.; Jenneson, P. M.

    1998-04-01

    Ion-beam analysis has been applied to a variety of problems involving diffusion in heterogeneous materials. An energy loss technique has been used to study both the diffusion of water and the surface segregation of fluoropolymers in polymeric matrices. A scanning micro-beam technique has been developed to allow water concentrations in hydrophilic polymers and cements to be measured together with associated solute elements. It has also been applied to the diffusion of shampoo into hair.

  10. Six tesla analyzing magnet for heavy-ion beam transport

    SciTech Connect

    Smith, R.P.; Bollinger, L.; Erskine, J.; Genens, L.; Hoffman, J.

    1980-01-01

    A superconducting analyzer magnet for particle beam deflection has been designed and is being fabricated for use at the Argonne Tandem-Linac Accelerator System (ATLAS). This six tesla magnet will provide 45/sup 0/ of deflection for the heavy-ion beams from the ATLAS tandem electrostatic accelerator and together with its twin will replace the existing conventional 90/sup 0/ analyzer magnet which will become inadequate when ATLAS is completed.

  11. Drift compression of an intense neutralized ion beam

    SciTech Connect

    Roy, P.K.; Yu, S.S.; Henestroza, E.; Anders, A.; Bieniosek, F.M.; Coleman, J.; Eylon, S.; Greenway, W.G.; Leitner, M.; Logan, B.G.; Waldron, W.L.; Welch, D.R.; Thoma, C.; Sefkow, A.B.; Gilson, E.P.; Efthimion, P.C.; Davidson, R.C.

    2004-10-25

    Longitudinal compression of a tailored-velocity, intense neutralized ion beam has been demonstrated. The compression takes place in a 1-2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces a head-to-tail velocity ramp that longitudinally compresses the neutralized beam, enhancing the beam peak current by a factor of 50 and producing a pulse duration of about 3 ns. this measurement has been confirmed independently with two different diagnostic systems.

  12. Theory of Nanocluster Size Distributions from Ion Beam Synthesis

    SciTech Connect

    Yuan, C.W.; Yi, D.O.; Sharp, I.D.; Shin, S.J.; Liao, C.Y.; Guzman, J.; Ager III, J.W.; Haller, E.E.; Chrzan, D.C.

    2008-06-13

    Ion beam synthesis of nanoclusters is studied via both kinetic Monte Carlo simulations and the self-consistent mean-field solution to a set of coupled rate equations. Both approaches predict the existence of a steady state shape for the cluster size distribution that depends only on a characteristic length determined by the ratio of the effective diffusion coefficient to the ion flux. The average cluster size in the steady state regime is determined by the implanted species/matrix interface energy.

  13. Focused ion beams using a high-brightness plasma source

    NASA Astrophysics Data System (ADS)

    Guharay, Samar

    2002-10-01

    High-brightness ion beams, with low energy spread, have merits for many new applications in microelectronics, materials science, and biology. Negative ions are especially attractive for the applications that involve beam-solid interactions. When negative ions strike a surface, especially an electrically isolated surface, the surface charging voltage is limited to few volts [1]. This property can be effectively utilized to circumvent problems due to surface charging, such as device damage and beam defocusing. A compact plasma source, with the capability to deliver either positive or negative ion beams, has been developed. H- beams from this pulsed source showed brightness within an order of magnitude of the value for beams from liquid-metal ion sources. The beam angular intensity is > 40 mAsr-1 and the corresponding energy spread is <2.5 eV [2]. Using a simple Einzel lens with magnification of about 0.1, a focused current density of about 40 mAcm-2 is obtained. It is estimated that an additional magnification of about 0.1 can yield a focused current density of > 1 Acm-2 and a spot size of 100 nm. Such characteristics of focused beam parameters, using a dc source, will immediately open up a large area of new applications. [1] P. N. Guzdar, A. S. Sharma, S. K. Guharay, "Charging of substrates irradiated by particle beams" Appl. Phys. Lett. 71, 3302 (1997). [2] S. K. Guharay, E. Sokolovsky, J. Orloff, "Characteristics of ion beams from a Penning source for focused ion beam applications" J. Vac. Sci Technol. B17, 2779 (1999).

  14. Maskless micro-ion-beam reduction lithography system

    DOEpatents

    Leung, Ka-Ngo; Barletta, William A.; Patterson, David O.; Gough, Richard A.

    2005-05-03

    A maskless micro-ion-beam reduction lithography system is a system for projecting patterns onto a resist layer on a wafer with feature size down to below 100 nm. The MMRL system operates without a stencil mask. The patterns are generated by switching beamlets on and off from a two electrode blanking system or pattern generator. The pattern generator controllably extracts the beamlet pattern from an ion source and is followed by a beam reduction and acceleration column.

  15. Tolerance of Normal Tissues to Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Habrand, Jean-Louis; Datchary, Jean; Pommier, Pascal; Bolle, Stéphanie; Feuvret, Loïc; Ghorbel, Ismael; Dendale, Remi

    This review from the radiation oncology literature provides tolerance doses of normal tissues, mainly late responding. It reports toxicity data for main organs based on the experience with photons, and similar data for various modes of ion beam therapy (protons, light ions, single or multifractionated). Although these data can help compare toxicity of both types of radiations, it should be remembered that clinical historical series are generally not strictly comparable.

  16. Is Prostate Cancer a Good Candidate for Ion Beam Therapy?

    NASA Astrophysics Data System (ADS)

    Rossi, Carl J.

    Organ-confined prostate cancer now constitutes one of the most commonly treated malignancies with ion beam therapy (IBT). Because of this, questions have been raised regarding the efficacy and cost-effectiveness of such treatment. This chapter details the clinical results obtained with both proton and carbon ion therapy, discusses ongoing clinical trials, and seeks to place IBT in the context of other technological evolutions in radiation oncology.

  17. Dynamics of heavy ion beams during longitudinal compression

    SciTech Connect

    Ho, D.D.M.; Bangerter, R.O.; Lee, E.P.; Brandon, S.; Mark, J.W.K.

    1987-03-13

    Heavy ion beams with initially uniform line charge density can be compressed longitudinally by an order of magnitude in such a way that the compressed beam has uniform line charge density and velocity-tilt profiles. There are no envelope mismatch oscillations during compression. Although the transverse temperature varies along the beam and also varies with time, no substantial longitudinal and transverse emittance growth has been observed. Scaling laws for beam radius and transport system parameters are given.

  18. Bilayer-metal assisted chemical etching of silicon microwire arrays for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Wu, R. W.; Yuan, G. D.; Wang, K. C.; Wei, T. B.; Liu, Z. Q.; Wang, G. H.; Wang, J. X.; Li, J. M.

    2016-02-01

    Silicon microwires with lateral dimension from 5 μm to 20 μm and depth as long as 20 μm are prepared by bilayer metal assisted chemical etching (MaCE). A bilayer metal configuration (Metal 1 / Metal 2) was applied to assist etching of Si where metal 1 acts as direct catalyst and metal 2 provides mechanical support. Different metal types were investigated to figure out the influence of metal catalyst on morphology of etched silicon. We find that silicon microwires with vertical side wall are produced when we use Ag/Au bilayer, while cone-like and porous microwires formed when Pt/Au is applied. The different micro-/nano-structures in as-etched silicon are demonstrated to be due to the discrepancy of work function of metal catalyst relative to Si. Further, we constructed a silicon microwire arrays solar cells in a radial p-n junction configurations in a screen printed aluminum paste p-doping process.

  19. Method and apparatus for efficient photodetachment and purification of negative ion beams

    DOEpatents

    Beene, James R [Oak Ridge, TN; Liu, Yuan [Knoxville, TN; Havener, Charles C [Knoxville, TN

    2008-02-26

    Methods and apparatus are described for efficient photodetachment and purification of negative ion beams. A method of purifying an ion beam includes: inputting the ion beam into a gas-filled multipole ion guide, the ion beam including a plurality of ions; increasing a laser-ion interaction time by collisional cooling the plurality of ions using the gas-filled multipole ion guide, the plurality of ions including at least one contaminant; and suppressing the at least one contaminant by selectively removing the at least one contaminant from the ion beam by electron photodetaching at least a portion of the at least one contaminant using a laser beam.

  20. Prospects of ion beam extraction and transport simulations (invited)

    SciTech Connect

    Spaedtke, Peter; Tinschert, K.; Lang, R.; Maeder, J.; Rossbach, J.; Stetson, J. W.; Celona, L.

    2008-02-15

    Beam profile measurements using viewing targets and emittance measurements with pepper pot devices have established new insights about the ion beam extracted from an electron cyclotron resonance ion source (ECRIS). In our measurements we have compared two different ECRISs of CAPRICE type, one source was equipped with a standard 1.0 T hexapole magnet, whereas for the other ion source a stronger hexapole magnet with a flux density of 1.2 T has been installed. The resulting ion beam profile for each individual charge state produced by different focal strengths of an optical element can be used to estimate the emittance, but it also shows the negative influence of the hexapole on the extracted ion beam. A hexapole correction would be desirable to improve further beam transport. A possible correction scheme will be discussed. All experimental observations can be reproduced by computer simulation if a magnetic plasma is assumed. When the Larmor radius for ions becomes small, collisions are negligible for the path of ions within the plasma. Low energy electrons are highly movable along the magnetic field lines and can compensate the ion space charge within the plasma chamber.

  1. Nuclear astrophysics at the Holifield Radioactive Ion Beam Facility

    SciTech Connect

    Blackmon, J.C.

    1996-10-01

    Reactions involving radioactive nuclei play an important role in explosive stellar events such as novae, supernovae, and X-ray bursts. The development of accelerated, proton-rich radioactive ion beams provides a tool for directly studying many of the reactions that fuel explosive hydrogen burning. The experimental nuclear astrophysics program at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory is centered on absolute cross section measurements of these reactions with radioactive ion beams. Beams of {sup 17}F and {sup 18}F, important nuclei in the hot-CNO cycle, are currently under development at HRIBF. Progress in the production of intense radioactive fluorine beams is reported. The Daresbury Recoil Separator (DRS) has been installed at HRIBF as the primary experimental station for nuclear astrophysics experiments. The DRS will be used to measure reactions in inverse kinematics with the techniques of direct recoil detection, delayed-activity recoil detection, and recoil-gamma coincidence measurements. The first astrophysics experiments to be performed at HRIBF, mA the application of the recoil separator in these measurements, are discussed.

  2. Temperature measurements during high flux ion beam irradiations

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  3. Surface Smoothing and etching by gas cluster ion beam

    NASA Astrophysics Data System (ADS)

    Song, J. H.; Choi, W. K.

    2003-08-01

    Ar and CO2 gas cluster ion beam with a few nm size were generated by an adiabatic expansion through Laval nozzle. The existence and the mean size distribution of the cluster were analyzed by time-of-flight measurement. Crater induced by Ar cluster ion beam and crown-like hillock by CO2 cluster ion impact on Si(100) were observed by an atomic force microcopy. CO2 cluster ion was irradiated on Si at 25 kV with the variations of ion dose from 1010 to 1013 cluster ions(CI)/cm2, at the flux of 109/cm2 s. Through this isolated cluster ion impact, the interaction mechanism between cluster ion with solid surface was suggested to be made of three steps: surface embossment, surface sputtering and smoothing, and surface etching. Another surface smoothing and etching experiment using CO2 cluster ion beam were carried out over ITO/glass and Cr-masked Si3N4 thin film surfaces at 25 kV.

  4. Simulations of Ion Beam Heated Targets on NDCX II

    NASA Astrophysics Data System (ADS)

    Barnard, J. J.; Friedman, A.; Perkins, L. J.; Bieniosek, F. M.; Hay, M. J.; Henestroza, E.; Logan, B. G.; More, R. M.; Ni, P. A.; Ng, S. F.; Yu, S. S.; Veitzer, S. A.

    2010-11-01

    The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator now being constructed at LBNL and scheduled for project completion in 2012. The design calls for a ˜2 - 3 MeV, ˜30 A Li^+ ion beam, delivered in a bunch with sub ns pulse duration, and transverse dimension less than ˜ 1 mm. The purpose of NDCX II is to carry out experimental studies of material in the warm dense matter regime and ion beam and hydrodynamic coupling experiments relevant to heavy ion fusion (HIF). In preparation for NDCX-II, we have carried out hydro simulations of ion-beam-heated, porous and solid, metallic and non-metallic, targets. We have shown the sensitivity of observables on equations of state. Pulse formats include single pulses of fixed ion energy, and and single or double pulses with variable energy to create shocks and investigate ion-coupling efficiency. Comparisons are made with simulations of ion driven direct drive HIF capsules.

  5. Nano-scale processes behind ion-beam cancer therapy

    NASA Astrophysics Data System (ADS)

    Surdutovich, Eugene; Garcia, Gustavo; Mason, Nigel; Solov'yov, Andrey V.

    2016-04-01

    This topical issue collates a series of papers based on new data reported at the third Nano-IBCT Conference of the COST Action MP1002: Nanoscale Insights into Ion Beam Cancer Therapy, held in Boppard, Germany, from October 27th to October 31st, 2014. The Nano-IBCT COST Action was launched in December 2010 and brought together more than 300 experts from different disciplines (physics, chemistry, biology) with specialists in radiation damage of biological matter from hadron-therapy centres, and medical institutions. This meeting followed the first and the second conferences of the Action held in October 2011 in Caen, France and in May 2013 in Sopot, Poland respectively. This conference series provided a focus for the European research community and has highlighted the pioneering research into the fundamental processes underpinning ion beam cancer therapy. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey V. Solov'yov, Nigel Mason, Gustavo Garcia and Eugene Surdutovich.

  6. Dense Metal Plasma in a Solenoid for Ion Beam Neutralization

    SciTech Connect

    Anders, Andre; Kauffeldt, Marina; Oks, Efim M.; Roy, Prabir K.

    2010-10-30

    Space-charge neutralization is required to compress and focus a pulsed, high-current ion beam on a target for warm dense matter physics or heavy ion fusion experiments. We described approaches to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary space-charge compensating electrons. Among the options are plasma injection from pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means, by an array of movable Langmuir probes, by a small single probe, and by evaluating Stark broadening of the Balmer H beta spectral line. In the main approach described here, the plasma is produced at several cathode spots distributed azimuthally on the ring cathode. It is shown that the plasma is essentially hollow, as determined by the structure of the magnetic field, though the plasma density exceeds 1014 cm-3 in practically all zones of the solenoid volume if the ring electrode is placed a few centimeters off the center of the solenoid. The plasma is non-uniform and fluctuating, however, since its density exceeds the ion beam density it is believed that this approach could provide a practical solution to the space charge neutralization challenge.

  7. Intense ion beam neutralization using underdense background plasma

    SciTech Connect

    Berdanier, William; Roy, Prabir K.; Kaganovich, Igor

    2015-01-15

    Producing an overdense background plasma for neutralization purposes with a density that is high compared to the beam density is not always experimentally possible. We show that even an underdense background plasma with a small relative density can achieve high neutralization of intense ion beam pulses. Using particle-in-cell simulations, we show that if the total plasma electron charge is not sufficient to neutralize the beam charge, electron emitters are necessary for effective neutralization but are not needed if the plasma volume is so large that the total available charge in the electrons exceeds that of the ion beam. Several regimes of possible underdense/tenuous neutralization plasma densities are investigated with and without electron emitters or dense plasma at periphery regions, including the case of electron emitters without plasma, which does not effectively neutralize the beam. Over 95% neutralization is achieved for even very underdense background plasma with plasma density 1/15th the beam density. We compare results of particle-in-cell simulations with an analytic model of neutralization and find close agreement with the particle-in-cell simulations. Further, we show experimental data from the National Drift Compression experiment-II group that verifies the result that underdense plasma can neutralize intense heavy ion beams effectively.

  8. Studies of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    NASA Astrophysics Data System (ADS)

    Stepanov, A.; Gilson, E. P.; Grisham, L.; Davidson, R. C.

    2013-10-01

    Space-charge forces limit the possible transverse compression of high perveance ion beams that are used in ion-beam-driven high energy density physics applications; the minimum radius to which a beam can be focused is an increasing function of perveance. The limit can be overcome if a plasma is introduced in the beam path between the focusing element and the target in order to neutralize the space charge of the beam. This concept has been implemented on the Neutralized Drift Compression eXperiment (NDCX) at LBNL using Ferroelectric Plasma Sources (FEPS). In our experiment at PPPL, we propagate a perveance-dominated ion beam through a FEPS to study the effect of the neutralizing plasma on the beam envelope and its evolution in time. A 30-60 keV space-charge-dominated Argon beam is focused with an Einzel lens into a FEPS located at the beam waist. The beam is intercepted downstream from the FEPS by a movable Faraday cup that provides time-resolved 2D current density profiles of the beam spot on target. We report results on: (a) dependence of charge neutralization on FEPS plasma density; (b) effects on beam emittance, and (c) time evolution of the beam envelope after the FEPS pulse. Research supported by the U.S. Department of Energy.

  9. Depth-dose relations for heavy ion beams

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.

    1977-01-01

    Radiation transport of heavy ions in matter is of interest to radiological protection in space and high-altitude aircraft. In addition, heavy ion beams are expected to be of advantage in radiotherapy since their characteristic Bragg curve allows a relative reduction of the dose in reaching a tumor site and the near elimination of exposure beyond the tumor region as the beam exits the body. Furthermore, the radioresistance of tumorous cells due to their hypoxic state may be reduced or eliminated by the high specific ionization of heavy ion beams. The depth-dose distribution of heavy ion beams consists of energy deposited by the attenuated primary beam with its characteristic Bragg curve and a relatively unstructured background due to secondary radiations produced in nuclear reactions. As the ion mass increases, the secondary contribution becomes more structured and may add significantly to the Bragg peak of the primary ions. The result for heavy ions (z greater than 20) is a greatly broadened Bragg peak region, especially in comparison to straggling effects, which may prove to be of importance in radiotherapy and biomedical research.

  10. Study on space charge compensation in negative hydrogen ion beam.

    PubMed

    Zhang, A L; Peng, S X; Ren, H T; Zhang, T; Zhang, J F; Xu, Y; Guo, Z Y; Chen, J E

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H(+) beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H(-) beam from a 2.45 GHz microwave driven H(-) ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results. PMID:26932087

  11. Ferroelectric Plasma Source for Heavy Ion Beam ChargeNeutralization

    SciTech Connect

    Efthimion, Philip C.; Gilson, Erik P.; Grisham, Larry; Davidson,Ronald C.; Yu, Simon; Waldron, William; Logan, B. Grant

    2005-10-01

    Plasmas are employed as a source of unbound electrons for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length {approx} 0.1-1 m would be suitable. To produce one-meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being developed. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source utilizes the ferroelectric ceramic BaTiO{sub 3} to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic, and high voltage ({approx} 1-5 kV) applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long has produced plasma densities of 5 x 10{sup 11} cm{sup -3}. The source was integrated into the previous Neutralized Transport Experiment (NTX), and successfully charge neutralized the K{sup +} ion beam. Presently, the one-meter source is being fabricated. The source is being characterized and will be integrated into NDCX for charge neutralization experiments.

  12. Study on space charge compensation in negative hydrogen ion beam.

    PubMed

    Zhang, A L; Peng, S X; Ren, H T; Zhang, T; Zhang, J F; Xu, Y; Guo, Z Y; Chen, J E

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H(+) beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H(-) beam from a 2.45 GHz microwave driven H(-) ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  13. Copper nanorod array assisted silicon waveguide polarization beam splitter.

    PubMed

    Kim, Sangsik; Qi, Minghao

    2014-04-21

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.

  14. Copper nanorod array assisted silicon waveguide polarization beam splitter

    PubMed Central

    Kim, Sangsik; Qi, Minghao

    2014-01-01

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology. PMID:24787839

  15. Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

    PubMed Central

    2014-01-01

    In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films. PMID:25349554

  16. Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method.

    PubMed

    Ouertani, Rachid; Hamdi, Abderrahmen; Amri, Chohdi; Khalifa, Marouan; Ezzaouia, Hatem

    2014-01-01

    In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films.

  17. Polyelectrolyte multilayer-assisted fabrication of non-periodic silicon nanocolumn substrates for cellular interface applications.

    PubMed

    Lee, Seyeong; Kim, Dongyoon; Kim, Seong-Min; Kim, Jeong-Ah; Kim, Taesoo; Kim, Dong-Yu; Yoon, Myung-Han

    2015-09-21

    Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical silicon nanocolumn arrays were successfully fabricated on a wafer scale, while each nanocolumn geometric factor, such as the diameter, height, density, and spatial patterning, could be fully controlled in an independent manner. Finally, we demonstrate that our vertical silicon nanocolumn substrates support viable cell culture with minimal cell penetration and unhindered cell motility due to the blunt nanocolumn morphology. These results suggest that vertical silicon nanocolumn substrates may serve as a useful cellular interface platform for performing a statistically meaningful number of cellular experiments in the fields of biomolecular delivery, stem cell research, etc.

  18. Extraction simulations and emittance measurements of a Holifield Radioactive Ion Beam Facility electron beam plasma source for radioactive ion beams

    SciTech Connect

    Mendez, II, Anthony J; Liu, Yuan

    2010-01-01

    The Holifield Radioactive Ion Beam Facility HRIBF at Oak Ridge National Laboratory has a variety of ion sources used to produce radioactive ion beams RIBs. Of these, the workhorse is an electron beam plasma EBP ion source. The recent addition of a second RIB injector, the Injector for Radioactive Ion Species 2 IRIS2, for the HRIBF tandem accelerator prompted new studies of the optics of the beam extraction from the EBP source. The source was modeled using SIMION V8.0, and results will be presented, including comparison of the emittances as predicted by simulation and as measured at the HRIBF offline ion source test facilities. Also presented will be the impact on phase space shape resulting from extraction optics modifications implemented at IRIS2.

  19. Extraction simulations and emittance measurements of a Holifield Radioactive Ion Beam Facility electron beam plasma source for radioactive ion beams

    SciTech Connect

    Mendez, A. J. II; Liu, Y.

    2010-02-15

    The Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory has a variety of ion sources used to produce radioactive ion beams (RIBs). Of these, the workhorse is an electron beam plasma (EBP) ion source. The recent addition of a second RIB injector, the Injector for Radioactive Ion Species 2 (IRIS2), for the HRIBF tandem accelerator prompted new studies of the optics of the beam extraction from the EBP source. The source was modeled using SIMION V8.0, and results will be presented, including comparison of the emittances as predicted by simulation and as measured at the HRIBF offline ion source test facilities. Also presented will be the impact on phase space shape resulting from extraction optics modifications implemented at IRIS2.

  20. Extraction Simulations and Emittance Measurements of a Holifield Radioactive Ion Beam Facility Electron Beam Plasma Source for Radioactive Ion Beams

    SciTech Connect

    Mendez, II, Anthony J; Liu, Yuan

    2010-01-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory has a variety of ion sources used to produce radioactive ion beams (RIBs). Of these, the workhorse is an electron beam plasma (EBP) ion source. The recent addition of a second RIB injector, the Injector for Radioactive Ion Species 2 (IRIS2), for the HRIBF tandem accelerator prompted new studies of the optics of the beam extraction from the EBP source. The source was modeled using SIMION V8.0, and results will be presented, including comparison of the emittances as predicted by simulation and as measured at the HRIBF offline ion source test facilities. Also presented will be the impact on phase space shape resulting from extraction optics modifications implemented at IRIS2.

  1. Self-pinched transport of intense ion beams

    SciTech Connect

    Ottinger, P.F.; Neri, J.M.; Stephanakis, S.J.

    1999-07-01

    Electron beams with substantial net currents have been routinely propagated in the self-pinched mode for the past two decades. However, as the physics of gas breakdown and beam neutralization is different for ion beams, previous predictions indicated insufficient net current for pinching so that ion beam self-pinched transport (SPT) was assumed impossible. Nevertheless, recent numerical simulations using the IPROP code have suggested that ion SPT is possible. These results have prompted initial experiments to investigate SPT of ion beams. A 100-kA, 1.2-MeV, 3-cm-radius proton beam, generated on the Gamble II pulsed-power accelerator at NRL, has been injected into helium in the 30- to 250-mTorr regime to study this phenomenon. Evidence of self-pinched ion beam transport was observed in the 35- to 80-mTorr SPT pressure window predicted by IPROP. Measured signals from a time- and space-resolved scattered proton diagnostic and a time-integrated Li(Cu) nuclear activation diagnostic, both of which measure protons striking a 10-cm diameter target 50 cm into the transport region, are significantly larger in this pressure window than expected for ballistic transport. These results are consistent with significant self-magnetic fields and self-pinching of the ion beam. On the other hand, time-integrated signals from these same two diagnostics are consistent with ballistic transport at pressures above and below the SPT window. Interferometric electron line-density measurements, acquired during beam injection into the helium gas, show insignificant ionization below 35 mTorr, a rapidly rising ionization fraction with pressure in the SPT window, and a plateau in ionization fraction at about 2% for pressures above 80 mTorr. These and other results are consistent with the physical picture for SPT. IPROP simulations, which closely model the Gamble II experimental conditions, produce results that are in qualitative agreement with the experimental results. The advantages of SPT for

  2. Light and heavy ion beam analysis of thin biological sections

    NASA Astrophysics Data System (ADS)

    Lee, Joonsup; Siegele, Rainer; Pastuovic, Zeljko; Hackett, Mark J.; Hunt, Nicholas H.; Grau, Georges E.; Cohen, David D.; Lay, Peter A.

    2013-07-01

    The application of ion beam analysis (IBA) techniques to thin biological sections (ThBS) presents unique challenges in sample preparation, data acquisition and analysis. These samples are often the end product of expensive, time-consuming experiments, which involve many steps that require careful attention. Analysis via several techniques can maximise the information that is collected from these samples. Particle-induced X-ray emission (PIXE) and Rutherford backscattering (RBS) spectroscopy are two generally non-destructive IBA techniques that use the same MeV ions and can be performed simultaneously. The use of heavy ion PIXE applied to thick samples has, in the past, resulted in X-ray spectra of a poorer quality when compared to those obtained with proton beams. One of the reasons for this is the shorter probing depth of the heavy ions, which does not affect thin sample analysis. Therefore, we have investigated and compared 3-MeV proton and 36-MeV carbon ion beams on 7-μm thick mouse brain sections at the ANSTO Heavy ion microprobe (HIMP). The application of a 36-MeV C4+ ion beam for PIXE mapping of ThBS on thin Si3N4 substrate windows produced spectra of high quality that displayed close to a nine-times gain in signal yield (Z2/q) when compared to those obtained for 3-MeV protons for P, S, Cl and K but not for Fe, Cu and Zn. Image quality was overall similar; however, some elements showed better contrast and features with protons whilst others showed improved contrast with a carbon ion beam. RBS spectra with high enough counting statistics were easily obtained with 3-MeV proton beams resulting in high resolution carbon maps, however, the count rate for nitrogen and oxygen was too low. The results demonstrate that on thin samples, 36-MeV C4+ will produce good quality PIXE spectra in less time; therefore, carbon ions may be advantageous depending on which element is being studied. However, these advantages may be outweighed by the inherent disadvantages including

  3. Intercomparison of ion beam analysis software for the simulation of backscattering spectra from two-dimensional structures

    NASA Astrophysics Data System (ADS)

    Mayer, M.; Malinský, P.; Schiettekatte, F.; Zolnai, Z.

    2016-10-01

    The codes RBS-MAST, STRUCTNRA, F95-Rough and CORTEO are simulation codes for ion beam analysis spectra from two- or three-dimensional sample structures. The codes were intercompared in a code-code comparison using an idealized grating structure and by comparison to experimental data from a silicon grating on tantalum interlayer. All codes are in excellent agreement at higher incident energies and not too large energy losses. At lower incident energies, grazing angles of incidence and/or larger energy losses plural scattering effects play an increasing role. Simulation codes with plural scattering capabilities offer higher accuracy and better agreement to experimental results in this regime.

  4. Ion assisted deposition of SiO2 film from silicon

    NASA Astrophysics Data System (ADS)

    Pham, Tuan. H.; Dang, Cu. X.

    2005-09-01

    Silicon dioxide, SiO2, is one of the preferred low index materials for optical thin film technology. It is often deposited by electron beam evaporation source with less porosity and scattering, relatively durable and can have a good laser damage threshold. Beside these advantages the deposition of critical optical thin film stacks with silicon dioxide from an E-gun was severely limited by the stability of the evaporation pattern or angular distribution of the material. The even surface of SiO2 granules in crucible will tend to develop into groove and become deeper with the evaporation process. As the results, angular distribution of the evaporation vapor changes in non-predicted manner. This report presents our experiments to apply Ion Assisted Deposition process to evaporate silicon in a molten liquid form. By choosing appropriate process parameters we can get SiO2 film with good and stable property.

  5. Mechanical Modulation of Phonon-Assisted Field Emission in a Silicon Nanomembrane Detector for Time-of-Flight Mass Spectrometry

    PubMed Central

    Park, Jonghoo; Blick, Robert H.

    2016-01-01

    We demonstrate mechanical modulation of phonon-assisted field emission in a free-standing silicon nanomembrane detector for time-of-flight mass spectrometry of proteins. The impacts of ion bombardment on the silicon nanomembrane have been explored in both mechanical and electrical points of view. Locally elevated lattice temperature in the silicon nanomembrane, resulting from the transduction of ion kinetic energy into thermal energy through the ion bombardment, induces not only phonon-assisted field emission but also a mechanical vibration in the silicon nanomembrane. The coupling of these mechanical and electrical phenomenon leads to mechanical modulation of phonon-assisted field emission. The thermal energy relaxation through mechanical vibration in addition to the lateral heat conduction and field emission in the silicon nanomembrane offers effective cooling of the nanomembrane, thereby allowing high resolution mass analysis. PMID:26861329

  6. Mechanical Modulation of Phonon-Assisted Field Emission in a Silicon Nanomembrane Detector for Time-of-Flight Mass Spectrometry.

    PubMed

    Park, Jonghoo; Blick, Robert H

    2016-01-01

    We demonstrate mechanical modulation of phonon-assisted field emission in a free-standing silicon nanomembrane detector for time-of-flight mass spectrometry of proteins. The impacts of ion bombardment on the silicon nanomembrane have been explored in both mechanical and electrical points of view. Locally elevated lattice temperature in the silicon nanomembrane, resulting from the transduction of ion kinetic energy into thermal energy through the ion bombardment, induces not only phonon-assisted field emission but also a mechanical vibration in the silicon nanomembrane. The coupling of these mechanical and electrical phenomenon leads to mechanical modulation of phonon-assisted field emission. The thermal energy relaxation through mechanical vibration in addition to the lateral heat conduction and field emission in the silicon nanomembrane offers effective cooling of the nanomembrane, thereby allowing high resolution mass analysis. PMID:26861329

  7. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U.; Yu, L. D.

    2015-12-01

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  8. Rapid Covalent Modification of Silicon Oxide Surfaces through Microwave-Assisted Reactions with Alcohols.

    PubMed

    Lee, Austin W H; Gates, Byron D

    2016-07-26

    We demonstrate the method of a rapid covalent modification of silicon oxide surfaces with alcohol-containing compounds with assistance by microwave reactions. Alcohol-containing compounds are prevalent reagents in the laboratory, which are also relatively easy to handle because of their stability against exposure to atmospheric moisture. The condensation of these alcohols with the surfaces of silicon oxides is often hindered by slow reaction kinetics. Microwave radiation effectively accelerates this condensation reaction by heating the substrates and/or solvents. A variety of substrates were modified in this demonstration, such as silicon oxide films of various thicknesses, glass substrates such as microscope slides (soda lime), and quartz. The monolayers prepared through this strategy demonstrated the successful formation of covalent surface modifications of silicon oxides with water contact angles of up to 110° and typical hysteresis values of 2° or less. An evaluation of the hydrolytic stability of these monolayers demonstrated their excellent stability under acidic conditions. The techniques introduced in this article were successfully applied to tune the surface chemistry of silicon oxides to achieve hydrophobic, oleophobic, and/or charged surfaces. PMID:27396288

  9. Rapid Covalent Modification of Silicon Oxide Surfaces through Microwave-Assisted Reactions with Alcohols.

    PubMed

    Lee, Austin W H; Gates, Byron D

    2016-07-26

    We demonstrate the method of a rapid covalent modification of silicon oxide surfaces with alcohol-containing compounds with assistance by microwave reactions. Alcohol-containing compounds are prevalent reagents in the laboratory, which are also relatively easy to handle because of their stability against exposure to atmospheric moisture. The condensation of these alcohols with the surfaces of silicon oxides is often hindered by slow reaction kinetics. Microwave radiation effectively accelerates this condensation reaction by heating the substrates and/or solvents. A variety of substrates were modified in this demonstration, such as silicon oxide films of various thicknesses, glass substrates such as microscope slides (soda lime), and quartz. The monolayers prepared through this strategy demonstrated the successful formation of covalent surface modifications of silicon oxides with water contact angles of up to 110° and typical hysteresis values of 2° or less. An evaluation of the hydrolytic stability of these monolayers demonstrated their excellent stability under acidic conditions. The techniques introduced in this article were successfully applied to tune the surface chemistry of silicon oxides to achieve hydrophobic, oleophobic, and/or charged surfaces.

  10. Fabrication of novel quantum cascade lasers using focused ion beam (FIB) processing

    NASA Astrophysics Data System (ADS)

    Ross, I. M.; Ng, W. H.; Wilson, L. R.; Luxmoore, I. J.; Cockburn, J. W.; Krysa, A.; Cullis, A. G.; Roberts, J. S.

    2006-02-01

    Focussed ion beam (FIB) processing has been applied to the fabrication of novel InP-based cleaved coupled cavity (CCC) quantum cascade lasers (QCL). Gas assisted etching using XeF2 has been shown to significantly reduce the redeposition of sputtered material onto the mirror surfaces during final milling. For the unprocessed laser a broad spread of lasing peaks are observed between 9.72µm to 9.78µm at a current of 380mA (1kA/cm-2). After FIB processing, substantial side mode suppression is observed on applying a current of 20mA (100A/cm-2) to the short section and the main lasing peak is observed at 9.77µm.

  11. Simulation of ion beam scattering in a gas stripper

    NASA Astrophysics Data System (ADS)

    Maxeiner, Sascha; Suter, Martin; Christl, Marcus; Synal, Hans-Arno

    2015-10-01

    Ion beam scattering in the gas stripper of an accelerator mass spectrometer (AMS) enlarges the beam phase space and broadens its energy distribution. As the size of the injected beam depends on the acceleration voltage through phase space compression, the stripper becomes a limiting factor of the overall system transmission especially for low energy AMS system in the sub MV region. The spatial beam broadening and collisions with the accelerator tube walls are a possible source for machine background and energy loss fluctuations influence the mass resolution and thus isotope separation. To investigate the physical processes responsible for these effects, a computer simulation approach was chosen. Monte Carlo simulation methods are applied to simulate elastic two body scattering processes in screened Coulomb potentials in a (gas) stripper and formulas are derived to correctly determine random collision parameters and free path lengths for arbitrary (and non-homogeneous) gas densities. A simple parametric form for the underlying scattering cross sections is discussed which features important scaling behaviors. An implementation of the simulation was able to correctly model the data gained with the TANDY AMS system at ETH Zurich. The experiment covered transmission measurements of uranium ions in helium and beam profile measurements after the ion beam passed through the He-stripper. Beam profiles measured up to very high stripper densities could be understood in full system simulations including the relevant ion optics. The presented model therefore simulates the fundamental physics of the interaction between an ion beam and a gas stripper reliably. It provides a powerful and flexible tool for optimizing existing AMS stripper geometries and for designing new, state of the art low energy AMS systems.

  12. APERIODIC MAGNETIC TURBULENCE PRODUCED BY RELATIVISTIC ION BEAMS

    SciTech Connect

    Niemiec, Jacek; Pohl, Martin; Bret, Antoine; Stroman, Thomas

    2010-02-01

    Magnetic-field generation by a relativistic ion beam propagating through an electron-ion plasma along a homogeneous magnetic field is investigated with 2.5D high-resolution particle-in-cell (PIC) simulations. The studies test predictions of a strong amplification of short-wavelength modes of magnetic turbulence upstream of nonrelativistic and relativistic parallel shocks associated with supernova remnants (SNRs), jets of active galactic nuclei, and gamma-ray bursts. We find a good agreement in the properties of the turbulence observed in our simulations compared with the dispersion relation calculated for linear waves with arbitrary orientation of k-vector. Depending on the parameters, the back-reaction on the ion beam leads to filamentation of the ambient plasma and the beam, which in turn influences the properties of the magnetic turbulence. For mildly and ultrarelativistic beams, the instability saturates at field amplitudes a few times larger than the homogeneous magnetic field strength. This result matches our recent studies of nonrelativistically drifting, hot cosmic-ray particles upstream of SNR shocks which indicated only a moderate magnetic-field amplification by nonresonant instabilities. We also demonstrate that the aperiodic turbulence generated by the beam can provide efficient particle scattering with a rate compatible with Bohm diffusion. Representing the ion beam as a constant external current, i.e., excluding a back-reaction of the magnetic turbulence on the beam, we observe nonresonant parallel modes with wavelength and growth rate as predicted by analytic calculations. In this unrealistic setup, the magnetic field is amplified to amplitudes far exceeding the homogeneous field, as observed in recent magnetohydrodynamic and PIC simulations.

  13. Arc-based smoothing of ion beam intensity on targets

    DOE PAGES

    Friedman, Alex

    2012-06-20

    Manipulating a set of ion beams upstream of a target, makes it possible to arrange a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy (“heavy-ion fusion”). Here, we consider an approach to such smoothing that is based on rapidly “wobbling” each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this ismore » sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. We also found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.« less

  14. Arc-based smoothing of ion beam intensity on targets

    SciTech Connect

    Friedman, Alex

    2012-06-20

    Manipulating a set of ion beams upstream of a target, makes it possible to arrange a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy (“heavy-ion fusion”). Here, we consider an approach to such smoothing that is based on rapidly “wobbling” each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. We also found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.

  15. Arc-based smoothing of ion beam intensity on targets

    SciTech Connect

    Friedman, Alex

    2012-06-15

    By manipulating a set of ion beams upstream of a target, it is possible to arrange for a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy ('heavy-ion fusion'). Here, we consider an approach to such smoothing that is based on rapidly 'wobbling' each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. It is found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.

  16. Contamination analysis of radioactive samples in focused ion beam instruments.

    PubMed

    Evelan, Audrey Ruth; Brey, Richard R

    2013-02-01

    The use of Focused Ion Beam (FIB) instrument's to analyze and prepare samples that are radioactive requires attentiveness to the materials that are dislodged and free inside the chamber. Radioactive sputtered material must be understood even when observed at trace concentrations. Measurements using liquid scintillation counting and high purity germanium detectors were used to evaluate contamination on accessible surfaces inside a focused ion beam chamber that was used in the preparation of samples that were radioactive. The maximum removable contamination found was 0.27 0.4 Bq cm(-2), on the focused ion beam wall with 0.24 0.019 Bq cm(-2) on the door. Although these magnitudes of removable contamination are inconsequential for activation products, these same magnitudes of actinides, for example 239Pu, would represent 3.2% of an Annual Limit of Intake. This might be considered significant if one examines the relatively infrequent use of this device for the preparation of radioactive samples. Predicted activities of sputtered material were found using the software Transport of Ions in Matter, estimating that 0.003% of a radioactive samples activity is released into the FIB chamber. A used secondary electron detector's activity was measured to be 383.7 8.1 Bq. Preferential build-up of sputtered materials due to temperature or static charge gradients was considered. No temperature gradients were observed. Static charge gradients were measured inside the chamber varying between 0.057% below the mean to 34% higher than the mean. However, the magnitudes of contamination measured did not correlate to static charge gradients. Deposition in the chamber appears to have no mechanical cause but rather is sporadic however, measureable. Experience to date has been limited to samples of low activity; nevertheless, contamination inside the chamber was observed. Users should anticipate higher levels of readily dispersible radioactive contamination within the FIB as sample activity

  17. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2008-08-01

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  18. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect

    Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2010-03-16

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  19. Laser ion source for high brightness heavy ion beam

    NASA Astrophysics Data System (ADS)

    Okamura, M.

    2016-09-01

    A laser ion source is known as a high current high charge state heavy ion source. However we place great emphasis on the capability to realize a high brightness ion source. A laser ion source has a pinpoint small volume where materials are ionized and can achieve quite uniform low temperature ion beam. Those features may enable us to realize very small emittance beams. In 2014, a low charge state high brightness laser ion source was successfully commissioned in Brookhaven National Laboratory. Now most of all the solid based heavy ions are being provided from the laser ion source for regular operation.

  20. Pulsed ion beam investigation of the kinetics of surface reactions

    NASA Technical Reports Server (NTRS)

    Horton, C. C.; Eck, T. G.; Hoffman, R. W.

    1989-01-01

    Pulsed ion beam measurements of the kinetics of surface reactions are discussed for the case where the width of the ion pulse is comparable to the measured reaction time, but short compared to the time between successive pulses. Theoretical expressions are derived for the time dependence of the ion-induced signals for linear surface reactions. Results are presented for CO emission from surface carbon and CF emission from Teflon induced by oxygen ion bombardment. The strengths and limitations of this technique are described.

  1. Cellular track model for study of heavy ion beams

    NASA Technical Reports Server (NTRS)

    Shinn, Judy L.; Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Ngo, Duc M.

    1993-01-01

    Track theory is combined with a realistic model of a heavy ion beam to study the effects of nuclear fragmentation on cell survival and biological effectiveness. The effects of secondary reaction products are studied as a function of depth in a water column. Good agreement is found with experimental results for the survival of human T-l cells exposed to monoenergetic carbon, neon, and argon beams under aerobic and hypoxia conditions. The present calculation, which includes the effect of target fragmentation, is a significant improvement over an earlier calculation because of the use of a vastly improved beam model with no change in the track theory or cellular response parameters.

  2. Pattern evolution during ion beam sputtering; reductionistic view

    NASA Astrophysics Data System (ADS)

    Kim, J.-H.; Kim, J.-S.

    2016-09-01

    The development of the ripple pattern during the ion beam sputtering (IBS) is expounded via the evolution of its constituent ripples. For that purpose, we perform numerical simulation of the ripple evolution that is based on Bradley-Harper model and its non-linear extension. The ripples are found to evolve via various well-defined processes such as ripening, averaging, bifurcation and their combinations, depending on their neighboring ripples. Those information on the growth kinetics of each ripple allow the detailed description of the pattern development in real space that the instability argument and the diffraction study both made in k-space cannot provide.

  3. The Scientific program with RIBRAS (Radioactive Ion Beams in Brasil)

    SciTech Connect

    Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Mendes, D. R. Jr.; Pires, K. C. C.; Morcelle, V.; Hussein, M. S.; Barioni, A.; Condori, R. Pampa; Morais, M. C.; Alcantara Nunez, J.; Camargo, O. Jr.; Otani, Y.; Leistenschneider, E.; Scarduelli, V.; Benjamim, E. A.; Arazi, A.; Assuncao, M.

    2009-06-03

    The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of Sao Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as {sup 6}He,{sup 8}Li,{sup 7}Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented.

  4. 22nd International Conference on Ion Beam Analysis

    NASA Astrophysics Data System (ADS)

    Radović, Iva Bogdanović; Jakšić, Milko; Fazinić, Stjepko

    2016-03-01

    This special issue of Nuclear Instruments and Methods in Physics Research B contains the proceedings of the 22nd International Conference on Ion Beam Analysis (IBA 2015). The conference was held in Grand Hotel 4 Opatijska Cvijeta in Opatija, Croatia, between 14th and 19th June 2015. Opatija, one of the Croatia's most famous touristic destinations, often called the pearl of the Adriatic, is celebrating this year 170 years of tourism. During the past, kings and emperors, writers, philosophers, poets and composers, but also scientists, used to stay in the town mainly built at the turn of the 20th century.

  5. Quasi-liquid states observed on ion beam microtextured surfaces

    NASA Technical Reports Server (NTRS)

    Rossnagel, S. M.; Robinson, R. S.

    1982-01-01

    Liquid-like properties have been observed on surface structures developed by means of ion beam microtexturing. The structures include cones, pyramids, or wavelike formations. The observed liquid-like effects are drips and ripples on the sides of cones, droplet formation, the apparent flow and coalescence of closely packed structures, wetting angle and other surface tension effects, and the bending of cones by additional heating. The bulk temperatures are in the range of 50-600 C. These effects are seen to some extent on Cu, Al, Au, Pb, and Ni substrates.

  6. Focused Ion Beam Microscopy of ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Bazylinski, Dennis A.; Kirschvink, Joseph L.; McKay, David S.; Vali, Hojatollah; Gibson, Everett K., Jr.; Romanek, Christopher S.

    2005-01-01

    Our aim is to understand the mechanism(s) of formation of carbonate assemblages in ALH84001. A prerequisite is that a detailed characterization of the chemical and physical properties of the carbonate be established. We present here analyses by transmission electron microscopy (TEM) of carbonate thin sections produced by both focused ion beam (FIB) sectioning and ultramicrotomy. Our results suggest that the formation of ALH84001 carbonate assemblages were produced by considerably more complex process(es) than simple aqueous precipitation followed by partial thermal decomposition as proposed by other investigators [e.g., 1-3].

  7. Heavy ion beam interaction with a direct-driven pellet

    NASA Astrophysics Data System (ADS)

    Someya, T.; Kikuchi, T.; Miyazawa, K.; Kawata, S.; Ogoyski, A. I.

    2006-06-01

    In heavy ion beam (HIB) inertial confinement fusion (ICF), key issues include beam illumination non-uniformity. In this study we simulate the HIB interaction with a direct-driven target. The main purposes of this study are to clarify the multi-HIB energy deposition non-uniformity onto a direct-driven target and to calculate the target hydrodynamics in HIF. The calculation results demonstrate that we can realize a rather low non-uniform energy deposition, for example, less than 2.0% even for a 32-HIBs irradiation system.

  8. Theory of Nanocluster Size Distributions from Ion Beam Synthesis

    SciTech Connect

    Yuan, C. W.; Yi, D. O.; Shin, S. J.; Liao, C. Y.; Guzman, J.; Haller, E. E.; Chrzan, D. C.; Sharp, I. D.; Ager, J. W. III

    2009-04-10

    Ion beam synthesis of nanoclusters is studied via both kinetic Monte Carlo simulations and the self-consistent mean-field solution to a set of coupled rate equations. Both approaches predict the existence of a steady-state shape for the cluster-size distribution that depends only on a characteristic length determined by the effective diffusion coefficient, the ion solubility, and the volumetric ion flux. The average cluster size in the steady-state regime is determined by the implanted species or matrix interface energy.

  9. Method of cold welding using ion beam technology

    NASA Technical Reports Server (NTRS)

    Sater, B. L. (Inventor)

    1981-01-01

    A method for cold welding metal joints is described. In order to remove the contamination layer on the surface of the metal, an ion beam generator is used in a vacuum environment. A gas, such as xenon or argon, is ionized and accelerated toward the metal surface. The beam of gas effectively sputters away the surface oxides and contamination layer so that clean underlying metal is exposed in the area to be welded. The use of this method allows cold welding with minimal deformation. Both similar and dissimilar metals can be cold welded with this method.

  10. Estimates of maximum trappable ion beam power in plasma channels

    NASA Astrophysics Data System (ADS)

    Watrous, J. J.; Olson, R. E.

    Conservation laws and solutions to the equations of motion for single particles have been used to obtained greatest lower bounds on the ion beam power that can be injected into and confined within plasma channels. These bounds are use in the evaluation of proposed light ion driven ICF experiments and reactor concepts. Simple estimates of trappable power based on conservation laws will be compared with estimates based on solutions to the equation of motion. Consequences of the results of these calculations to current design studies will be discussed.

  11. The prospects of a subnanometer focused neon ion beam.

    PubMed

    Rahman, F H M; McVey, Shawn; Farkas, Louis; Notte, John A; Tan, Shida; Livengood, Richard H

    2012-01-01

    The success of the helium ion microscope has encouraged extensions of this technology to produce beams of other ion species. A review of the various candidate ion beams and their technical prospects suggest that a neon beam might be the most readily achieved. Such a neon beam would provide a sputtering yield that exceeds helium by an order of magnitude while still offering a theoretical probe size less than 1-nm. This article outlines the motivation for a neon gas field ion source, the expected performance through simulations, and provides an update of our experimental progress. PMID:21796647

  12. Ion beam analysis in cultural heritage studies: Milestones and perspectives

    SciTech Connect

    Dran, Jean-Claude; Calligaro, Thomas

    2013-07-18

    For three decades, ion beam analysis (IBA) in external mode was considered as the best choice for the characterisation of cultural heritage materials, as it combines excellent analytical performance and non-invasive character. However, in recent years, other analytical techniques arose as serious competitors, such as those based on synchrotron radiation (X-ray absorption, fluorescence or diffraction) or those using portable instruments (XRF, micro-Raman). It is shown that nevertheless IBA remains unmatched thanks to two unique features, namely the analysis of light elements and the high-resolution 3D chemical imaging.

  13. Shielding and Radiation Protection in Ion Beam Therapy Facilities

    NASA Astrophysics Data System (ADS)

    Wroe, Andrew J.; Rightnar, Steven

    Radiation protection is a key aspect of any radiotherapy (RT) department and is made even more complex in ion beam therapy (IBT) by the large facility size, secondary particle spectra and intricate installation of these centers. In IBT, large and complex radiation producing devices are used and made available to the public for treatment. It is thus the responsibility of the facility to put in place measures to protect not only the patient but also the general public, occupationally and nonoccupationally exposed personnel working within the facility, and electronics installed within the department to ensure maximum safety while delivering maximum up-time.

  14. Range and Energy Straggling in Ion Beam Transport

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Tai, Hsiang

    2000-01-01

    A first-order approximation to the range and energy straggling of ion beams is given as a normal distribution for which the standard deviation is estimated from the fluctuations in energy loss events. The standard deviation is calculated by assuming scattering from free electrons with a long range cutoff parameter that depends on the mean excitation energy of the medium. The present formalism is derived by extrapolating Payne's formalism to low energy by systematic energy scaling and to greater depths of penetration by a second-order perturbation. Limited comparisons are made with experimental data.

  15. Narrow conducting channels defined by helium ion beam damage

    SciTech Connect

    Cheeks, T.L.; Roukes, M.L.; Scherer, A.; Craighead, H.G.

    1988-11-14

    We have developed a new technique for patterning narrow conducting channels in GaAs-AlGaAs two-dimensional electron gas (2DEG) materials. A low-energy He ion beam successfully patterned narrow wires with little or no etching of the thin GaAs cap. The damage propagation of the He ion even at low energies was sufficient to decrease the mobility of the 2DEG located deep within the structure. The damage can be removed by a low-temperature anneal but remains stable at room temperature. Conducting channels as narrow as 300 nm have been fabricated and measured using low-temperature magnetoresistance.

  16. Photoluminescence Imaging of Focused Ion Beam Induced Individual Quantum Dots

    SciTech Connect

    Lee, Jieun; Saucer, Timothy W.; Martin, Andrew J.; Tien, Deborah; Millunchick, Joanna M.; Sih, Vanessa

    2011-02-08

    We report on scanning microphotoluminescence measurements that spectrally and spatially resolve emission from individual InAs quantum dots that were induced by focused ion beam patterning. Multilayers of quantum dots were spaced 2 μm apart, with a minimum single dot emission line width of 160 μeV, indicating good optical quality for dots patterned using this technique. Mapping 16 array sites, at least 65% were occupied by optically active dots and the spectral inhomogeneity was within 30 meV.

  17. The prospects of a subnanometer focused neon ion beam.

    PubMed

    Rahman, F H M; McVey, Shawn; Farkas, Louis; Notte, John A; Tan, Shida; Livengood, Richard H

    2012-01-01

    The success of the helium ion microscope has encouraged extensions of this technology to produce beams of other ion species. A review of the various candidate ion beams and their technical prospects suggest that a neon beam might be the most readily achieved. Such a neon beam would provide a sputtering yield that exceeds helium by an order of magnitude while still offering a theoretical probe size less than 1-nm. This article outlines the motivation for a neon gas field ion source, the expected performance through simulations, and provides an update of our experimental progress.

  18. Ion-beam-enhanced adhesion in the electronic stopping region

    NASA Technical Reports Server (NTRS)

    Griffith, J. E.; Qiu, Y.; Tombrello, T. A.

    1981-01-01

    The use of ion beams in the electronic stopping region to improve the adhesion of insulators to other materials is described. In particular, the bonding of Au films to Teflon, ferrite, and SiO2 was improved by bombarding them with He and Cl, respectively. Improvements in bonding were also observed for Au on glass, Au and Cu on sapphire, and Si3N4 on Si. The mechanism is apparently associated with sputtering and track forming processes occurring in the electronic stopping region. Some applications are discussed.

  19. Multiscale physics of ion-beam cancer therapy

    NASA Astrophysics Data System (ADS)

    Surdutovich, E.; Solov'yov, A. V.

    2012-07-01

    We review a multiscale approach to the physics of ion-beam cancer therapy, an approach suggested in order to understand the interplay of a large number of phenomena involved in radiation damage scenario occurring on a range of temporal, spatial, and energy scales. We briefly overview its history and present the current stage of its development. The differences of the multiscale approach from other methods of understanding and assessment of radiation damage are discussed as well as its relationship to other branches of physics, chemistry and biology.

  20. Ion Beam Etching: Replication of Micro Nano-structured 3D Stencil Masks

    SciTech Connect

    Weber, Patrick; Guibert, Edouard; Mikhailov, Serguei; Bruegger, Juergen; Villanueva, Guillermo

    2009-03-10

    Ion beam LIGA allows the etching of 3D nano-structures by direct writing with a nano-sized beam. However, this is a relatively time consuming process. We propose here another approach for etching structures on large surfaces and faster, compared to the direct writing process. This approach consists of replicating 3D structured masks, by scanning an unfocused ion beam. A polymer substrate is placed behind the mask, as in UV photolithography. But the main advantage is that the 3D structure of the mask can be replicated into the polymer. For that purpose, the masks (developped at LMIS1, EPFL) are made of a silicon nitride membrane 100 nm thick, on which 3D gold structures up to 200 nm thick, are deposited. The 3D Au structures are made with the nanostencil method, based on successive gold deposition. The IMA institute, from HE-Arc, owns a High Voltage Engineering 1.7 MV Tandetron with both solid and gaseous negative ion sources, able to generate ions from almost every chemical element in a broad range of energies comprised between 400 keV and 6.8 MeV. The beam composition and energy are chosen in such a way, that ions lose a significant fraction of their energy when passing through the thickest regions of the mask. Ions passing through thinner regions of the mask loose a smaller fraction of their energy and etch the polymer with larger thicknesses, allowing a replication of the mask into the polymer. For our trials, we have used a carbon beam with an energy of 500 keV. The beam was focussed to a diameter of 5 mm with solid slits, in order to avoid border effects and thus ensure a homogeneous dose distribution on the beam diameter. The feasibility of this technique has been demonstrated, allowing industrial applications for micro-mould fabrication, micro-fluidics and micro-optics.

  1. Investigations of a flat-panel detector for quality assurance measurements in ion beam therapy.

    PubMed

    Hartmann, Bernadette; Telsemeyer, Julia; Huber, Lucas; Ackermann, Benjamin; Jäkel, Oliver; Martišíková, Mária

    2012-01-01

    Increased accuracy in radiation delivery to a patient provided by scanning particle beams leads to high demands on quality assurance (QA). To meet the requirements, an extensive quality assurance programme has been implemented at the Heidelberg Ion Beam Therapy Center. Currently, high-resolution radiographic films are used for beam spot position measurements and homogeneity measurements for scanned fields. However, given that using this film type is time and equipment demanding, considerations have been made to replace the radiographic films in QA by another appropriate device. In this study, the suitability of the flat-panel detector RID 256 L based on amorphous silicon was investigated as an alternative method. The currently used radiographic films were taken as a reference. Investigations were carried out for proton and carbon ion beams. The detectors were irradiated simultaneously to allow for a direct comparison. The beam parameters (e.g. energy, focus, position) currently used in the daily QA procedures were applied. Evaluation of the measurements was performed using newly implemented automatic routines. The results for the flat-panel detector were compared to the standard radiographic films. Additionally, a field with intentionally decreased homogeneity was applied to test the detector's sensitivities toward possible incorrect scan parameters. For the beam position analyses, the flat-panel detector results showed good agreement with radiographic films. For both detector types, deviations between measured and planned spot distances were found to be below 1% (1 mm). In homogeneously irradiated fields, the flat-panel detector showed a better dose response homogeneity than the currently used radiographic film. Furthermore, the flat-panel detector is sensitive to field irregularities. The flat-panel detector was found to be an adequate replacement for the radiographic film in QA measurements. In addition, it saves time and equipment because no post

  2. Electrical trimming of ion-beam-sputtered polysilicon resistors by high current pulses

    NASA Astrophysics Data System (ADS)

    Das, Soumen; Lahiri, Samir K.

    1994-08-01

    Phosphorus doped polysilicon resistors have been fabricated from microcrystalline silicon films which were deposited by ion beam sputtering using an argon ion beam of diameter 3 cm, energy 1 keV and current density 7mA/cm(sup 2), with a deposition rate of 100-120 angstrom/min. The resistors, having a sheet resistance of 70 Omega /square and a carrier concentration of 7.5 x 10(sup 19)cm(sup - 3), were stressed with current pulses of width 10 mu s and duty cycle 0.6% for 5 min. There was a steady decrease of resistance with increasing pulse current density above a threshold value 5 x 10(sup 5)A/cm(sup 2). A maximum fall of 27% was observed for a 95 micron long resistor. The current-voltage characteristics were also recorded during the trimming process. The trimming characteristics were simulated using a small-signal resistivity model of Lu et al. (11) and the I-V characteristics by a large-bias conduction model (12) . A close fitting of the experimental data with the theoretical values needed an adjustment of some grain boundary parameters for the different pulse current densities used for stressing. The nature of variation of the grain boundary parameters indicates that the rapid Joule heating of the grain boundaries due to current pulses passivates the grain boundary interfaces, at lower currents above the threshold, and then, at higher values of currents, causes zone melting and gradual recrystallization of the disordered boundary layers and subsequent dopant segregation. It confirms the mechanism suggested in the physical model of Kato et al. (7) . The role played by the field-enhanced diffusivity and electromigration of dopant ions, due to the high instantaneous temperature of the grain boundaries, has also been discussed. The pulse trimming technique is simple and does not cause damage to the adjacent components on a monolithic chip.

  3. Mechanisms of material removal and mass transport in focused ion beam nanopore formation

    SciTech Connect

    Das, Kallol Johnson, Harley T.; Freund, Jonathan B.

    2015-02-28

    Despite the widespread use of focused ion beam (FIB) processing as a material removal method for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing, the basic material removal mechanisms of FIB processing are not well understood. We present the first complete atomistic simulation of high-flux FIB using large-scale parallel molecular dynamics (MD) simulations of nanopore fabrication in freestanding thin films. We focus on the root mechanisms of material removal and rearrangement and describe the role of explosive boiling in forming nanopores. FIB nanopore fabrication is typically understood to occur via sputter erosion. This can be shown to be the case in low flux systems, where individual ion impacts are sufficiently separated in time that they may be considered as independent events. But our detailed MD simulations show that in high flux FIB processing, above a threshold level at which thermal effects become significant, the primary mechanism of material removal changes to a significantly accelerated, thermally dominated process. Under these conditions, the target is heated by the ion beam faster than heat is conducted away by the material, leading quickly to melting, and then continued heating to nearly the material critical temperature. This leads to explosive boiling of the target material with spontaneous bubble formation and coalescence. Mass is rapidly rearranged at the atomistic scale, and material removal occurs orders of magnitude faster than would occur by simple sputtering. While the phenomenology is demonstrated computationally in silicon, it can be expected to occur at lower beam fluxes in other cases where thermal conduction is suppressed due to material properties, geometry, or ambient thermal conditions.

  4. Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Kal, S.; Kasko, I.; Ryssel, H.

    1995-10-01

    The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (<50 nm) CoSi2 preparation. A comparison of the plan-view and cross-section TEM micrographs of the ion-beam mixed and unmixed CoSi2 films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

  5. Non-invasive monitoring of therapeutic carbon ion beams in a homogeneous phantom by tracking of secondary ions.

    PubMed

    Gwosch, K; Hartmann, B; Jakubek, J; Granja, C; Soukup, P; Jäkel, O; Martišíková, M

    2013-06-01

    Radiotherapy with narrow scanned carbon ion beams enables a highly accurate treatment of tumours while sparing the surrounding healthy tissue. Changes in the patient's geometry can alter the actual ion range in tissue and result in unfavourable changes in the dose distribution. Consequently, it is desired to verify the actual beam delivery within the patient. Real-time and non-invasive measurement methods are preferable. Currently, the only technically feasible method to monitor the delivered dose distribution within the patient is based on tissue activation measurements by means of positron emission tomography (PET). An alternative monitoring method based on tracking of prompt secondary ions leaving a patient irradiated with carbon ion beams has been previously suggested. It is expected to help in overcoming the limitations of the PET-based technique like physiological washout of the beam induced activity, low signal and to allow for real-time measurements. In this paper, measurements of secondary charged particle tracks around a head-sized homogeneous PMMA phantom irradiated with pencil-like carbon ion beams are presented. The investigated energies and beam widths are within the therapeutically used range. The aim of the study is to deduce properties of the primary beam from the distribution of the secondary charged particles. Experiments were performed at the Heidelberg Ion Beam Therapy Center, Germany. The directions of secondary charged particles emerging from the PMMA phantom were measured using an arrangement of two parallel pixelated silicon detectors (Timepix). The distribution of the registered particle tracks was analysed to deduce its dependence on clinically important beam parameters: beam range, width and position. Distinct dependencies of the secondary particle tracks on the properties of the primary carbon ion beam were observed. In the particular experimental set-up used, beam range differences of 1.3 mm were detectable. In addition, variations in

  6. Non-invasive monitoring of therapeutic carbon ion beams in a homogeneous phantom by tracking of secondary ions.

    PubMed

    Gwosch, K; Hartmann, B; Jakubek, J; Granja, C; Soukup, P; Jäkel, O; Martišíková, M

    2013-06-01

    Radiotherapy with narrow scanned carbon ion beams enables a highly accurate treatment of tumours while sparing the surrounding healthy tissue. Changes in the patient's geometry can alter the actual ion range in tissue and result in unfavourable changes in the dose distribution. Consequently, it is desired to verify the actual beam delivery within the patient. Real-time and non-invasive measurement methods are preferable. Currently, the only technically feasible method to monitor the delivered dose distribution within the patient is based on tissue activation measurements by means of positron emission tomography (PET). An alternative monitoring method based on tracking of prompt secondary ions leaving a patient irradiated with carbon ion beams has been previously suggested. It is expected to help in overcoming the limitations of the PET-based technique like physiological washout of the beam induced activity, low signal and to allow for real-time measurements. In this paper, measurements of secondary charged particle tracks around a head-sized homogeneous PMMA phantom irradiated with pencil-like carbon ion beams are presented. The investigated energies and beam widths are within the therapeutically used range. The aim of the study is to deduce properties of the primary beam from the distribution of the secondary charged particles. Experiments were performed at the Heidelberg Ion Beam Therapy Center, Germany. The directions of secondary charged particles emerging from the PMMA phantom were measured using an arrangement of two parallel pixelated silicon detectors (Timepix). The distribution of the registered particle tracks was analysed to deduce its dependence on clinically important beam parameters: beam range, width and position. Distinct dependencies of the secondary particle tracks on the properties of the primary carbon ion beam were observed. In the particular experimental set-up used, beam range differences of 1.3 mm were detectable. In addition, variations in

  7. Susceptor Assisted Microwave Annealing Of Ion Implanted Silicon

    NASA Astrophysics Data System (ADS)

    Vemuri, Rajitha

    This thesis discusses the use of low temperature microwave anneal as an alternative technique to recrystallize materials damaged or amorphized due to implantation techniques. The work focuses on the annealing of high- Z doped Si wafers that are incapable of attaining high temperatures required for recrystallizing the damaged implanted layers by microwave absorption The increasing necessity for quicker and more efficient processing techniques motivates study of the use of a single frequency applicator microwave cavity along with a Fe2O3 infused SiC-alumina susceptor/applicator as an alternative post implantation process. Arsenic implanted Si samples of different dopant concentrations and implantation energies were studied pre and post microwave annealing. A set of as-implanted Si samples were also used to assess the effect of inactive dopants against presence of electrically active dopants on the recrystallization mechanisms. The extent of damage repair and Si recrystallization of the damage caused by arsenic and Si implantation of Si is determined by cross-section transmission electron microscopy and Raman spectroscopy. Dopant activation is evaluated for the As implanted Si by sheet resistance measurements. For the same, secondary ion mass spectroscopy analysis is used to compare the extent of diffusion that results from such microwave annealing with that experienced when using conventional rapid thermal annealing (RTA). Results show that compared to susceptor assisted microwave annealing, RTA caused undesired dopant diffusion. The SiC-alumina susceptor plays a predominant role in supplying heat to the Si substrate, and acts as an assistor that helps a high-Z dopant like arsenic to absorb the microwave energy using a microwave loss mechanism which is a combination of ionic and dipole losses. Comparisons of annealing of the samples were done with and without the use of the susceptor, and confirm the role played by the susceptor, since the samples donot recrystallize

  8. Slit disk for modified faraday cup diagnostic for determining power density of electron and ion beams

    DOEpatents

    Teruya, Alan T.; Elmer; John W.; Palmer, Todd A.

    2011-03-08

    A diagnostic system for characterization of an electron beam or an ion beam includes an electrical conducting disk of refractory material having a circumference, a center, and a Faraday cup assembly positioned to receive the electron beam or ion beam. At least one slit in the disk provides diagnostic characterization of the electron beam or ion beam. The at least one slit is located between the circumference and the center of the disk and includes a radial portion that is in radial alignment with the center and a portion that deviates from radial alignment with the center. The electron beam or ion beam is directed onto the disk and translated to the at least one slit wherein the electron beam or ion beam enters the at least one slit for providing diagnostic characterization of the electron beam or ion beam.

  9. First experimental-based characterization of oxygen ion beam depth dose distributions at the Heidelberg Ion-Beam Therapy Center

    NASA Astrophysics Data System (ADS)

    Kurz, C.; Mairani, A.; Parodi, K.

    2012-08-01

    Over the last decades, the application of proton and heavy-ion beams to external beam radiotherapy has rapidly increased. Due to the favourable lateral and depth dose profile, the superposition of narrow ion pencil beams may enable a highly conformal dose delivery to the tumour, with better sparing of the surrounding healthy tissue in comparison to conventional radiation therapy with photons. To fully exploit the promised clinical advantages of ion beams, an accurate planning of the patient treatments is required. The clinical treatment planning system (TPS) at the Heidelberg Ion-Beam Therapy Center (HIT) is based on a fast performing analytical algorithm for dose calculation, relying, among others, on laterally integrated depth dose distributions (DDDs) simulated with the FLUKA Monte Carlo (MC) code. Important input parameters of these simulations need to be derived from a comparison of the simulated DDDs with measurements. In this work, the first measurements of 16O ion DDDs at HIT are presented with a focus on the determined Bragg peak positions and the understanding of factors influencing the shape of the distributions. The measurements are compared to different simulation approaches aiming to reproduce the acquired data at best. A simplified geometrical model is first used to optimize important input parameters, not known a priori, in the simulations. This method is then compared to a more realistic, but also more time-consuming simulation approach better accounting for the experimental set-up and the measuring process. The results of this work contributed to a pre-clinical oxygen ion beam database, which is currently used by a research TPS for corresponding radio-biological cell experiments. A future extension to a clinical database used by the clinical TPS at HIT is foreseen. As a side effect, the performed investigations showed that the typical water equivalent calibration approach of experimental data acquired with water column systems leads to slight

  10. The SPES Radioactive Ion Beam facility of INFN

    NASA Astrophysics Data System (ADS)

    de Angelis, G.; Spes Collaboration; Prete, G.; Andrighetto, A.; Manzolaro, M.; Corradetti, S.; Scarpa, D.; Rossignoli, M.; Monetti, A.; Lollo, M.; Calderolla, M.; Vasquez, J.; Zafiropoulos, D.; Sarchiapone, L.; Benini, D.; Favaron, P.; Rigato, M.; Pegoraro, R.; Maniero, D.; Calabretta, L.; Comunian, M.; Maggiore, M.; Lombardi, A.; Piazza, L.; Porcellato, A. M.; Roncolato, C.; Bisoffi, G.; Pisent, A.; Galatà, A.; Giacchini, M.; Bassato, G.; Canella, S.; Gramegna, F.; Valiente, J.; Bermudez, J.; Mastinu, P. F.; Esposito, J.; Wyss, J.; Russo, A.; Zanella, S.

    2015-02-01

    A new Radioactive Ion Beam (RIB) facility (SPES) is presently under construction at the Legnaro National Laboratories of INFN. The SPES facility is based on the ISOL method using an UCx Direct Target able to sustain a power of 10 kW. The primary proton beam is provided by a high current Cyclotron accelerator with energy of 40 MeV and a beam current of 0.2-0.5 mA. Neutron-rich radioactive ions are produced by proton induced fission at an expected fission rate of the order of 1013 fissions per second. After ionization and selection the exotic isotopes are re-accelerated by the ALPI superconducting LINAC at energies of 10A MeV for masses in the region A=130 amu. The expected secondary beam rates are of the order of 107 - 109 pps. Aim of the SPES facility is to deliver high intensity radioactive ion beams of neutron rich nuclei for nuclear physics research as well as to be an interdisciplinary research center for radio-isotopes production for medicine and for neutron beams.

  11. The SPES Radioactive-Ion Beam Facility of INFN

    NASA Astrophysics Data System (ADS)

    de Angelis, G.; Prete, G.; Andrighetto, A.; Manzolaro, M.; Corradetti, S.; Scarpa, D.; Rossignoli, M.; Monetti, A.; Lollo, M.; Calderolla, M.; Vasquez, J.; Zafiropoulos, D.; Sarchiapone, L.; Benini, D.; Favaron, P.; Rigato, M.; Pegoraro, R.; Maniero, D.; Comunian, M.; Maggiore, M.; Lombardi, A.; Piazza, L.; Porcellato, A. M.; Roncolato, C.; Bisoffi, G.; Pisent, A.; Galatà, A.; Giacchini, M.; Bassato, G.; Canella, S.; Gramegna, F.; Valiente, J.; Bermudez, J.; Mastinu, P. F.; Esposito, J.; Wyss, J.; Russo, A.; Zanella, S.; Calabretta, L.

    2015-11-01

    A new radioactive-ion beam (RIB) facility (SPES) is presently under construction at the Legnaro National Laboratories of INFN. The SPES facility is based on the ISOL method using a UCx direct target able to sustain a power of 10 kW. The primary proton beam will be provided by a high-current cyclotron accelerator with energy of 35-70 MeV and a beam current of 0.2-0.5 mA. Neutron-rich radioactive ions will be produced by proton-induced fission on a uranium target at an expected fission rate of the order of 1013 fissions per second. After ionization and selection the exotic isotopes will be re-accelerated by the ALPI superconducting LINAC at energies of 10A MeV for masses in the region A=130 amu. The expected secondary beam rates are of the order of 107-109 pps. The aim of the SPES facility is to deliver high-intensity radioactive-ion beams of neutron-rich nuclei for nuclear physics research, as well as to be an interdisciplinary research center for radioisotope production for medicine and for neutron beams.

  12. The SPES radioactive ion beam project of INFN

    NASA Astrophysics Data System (ADS)

    de Angelis, Giacomo; Spes Collaboration; Prete, G.; Andrighetto, A.; Manzolaro, M.; Corradetti, S.; Scarpa, D.; Rossignoli, M.; Monetti, A.; Lollo, M.; Calderolla, M.; Vasquez, J.; Zafiropoulos, D.; Sarchiapone, L.; Benini, D.; Favaron, P.; Rigato, M.; Pegoraro, R.; Maniero, D.; Calabretta, L.; Comunian, M.; Maggiore, M.; Lombardi, A.; Piazza, L.; Porcellato, A. M.; Roncolato, C.; Bisoffi, G.; Pisent, A.; Galatà, A.; Giacchini, M.; Bassato, G.; Canella, S.; Gramegna, F.; Valiente, J.; Bermudez, J.; Mastinu, P. F.; Esposito, J.; Wyss, J.; Russo, A.; Zanella, S.

    2014-07-01

    The SPES Radioactive Ion Beam facility at INFN-LNL is presently in the construction phase. The facility is based on the Isol (Isotope separation on-line) method with an UCx Direct Target able to sustain a power of 10 kW. The primary proton beam is provided by a high current Cyclotron accelerator with energy of 35-70 MeV and a beam current of 0.20.5 mA. Neutron-rich radioactive ions are produced by proton induced Uranium fission at an expected fission rate of the order of 1013 fissions per second. After ionization and selection the exotic isotopes are re-accelerated by the ALPI superconducting Linac at energies of 10A MeV for masses in the region A = 130 amu. The expected secondary beam rates are of the order of 107 - 109 pps. Aim of the SPES project is to provide a facility for high intensity radioactive ion beams for nuclear physics research as well as to develop an interdisciplinary research center based on the cyclotron proton beam.

  13. Advanced techniques for characterization of ion beam modified materials

    SciTech Connect

    Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; Kluth, Patrick; Tuomisto, Filip

    2014-10-30

    Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiation effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.

  14. Data-driven RBE parameterization for helium ion beams.

    PubMed

    Mairani, A; Magro, G; Dokic, I; Valle, S M; Tessonnier, T; Galm, R; Ciocca, M; Parodi, K; Ferrari, A; Jäkel, O; Haberer, T; Pedroni, P; Böhlen, T T

    2016-01-21

    Helium ion beams are expected to be available again in the near future for clinical use. A suitable formalism to obtain relative biological effectiveness (RBE) values for treatment planning (TP) studies is needed. In this work we developed a data-driven RBE parameterization based on published in vitro experimental values. The RBE parameterization has been developed within the framework of the linear-quadratic (LQ) model as a function of the helium linear energy transfer (LET), dose and the tissue specific parameter (α/β)ph of the LQ model for the reference radiation. Analytic expressions are provided, derived from the collected database, describing the RBEα = αHe/αph and Rβ = βHe/βph ratios as a function of LET. Calculated RBE values at 2 Gy photon dose and at 10% survival (RBE10) are compared with the experimental ones. Pearson's correlation coefficients were, respectively, 0.85 and 0.84 confirming the soundness of the introduced approach. Moreover, due to the lack of experimental data at low LET, clonogenic experiments have been performed irradiating A549 cell line with (α/β)ph = 5.4 Gy at the entrance of a 56.4 MeV u(-1)He beam at the Heidelberg Ion Beam Therapy Center. The proposed parameterization reproduces the measured cell survival within the experimental uncertainties. A RBE formula, which depends only on dose, LET and (α/β)ph as input parameters is proposed, allowing a straightforward implementation in a TP system.

  15. Summary of the Working Group 2: Ion beams from plasmas

    NASA Astrophysics Data System (ADS)

    Fuchs, Julien

    2014-03-01

    The production of ion beams by high-power, short-pulse lasers [1] has been the focus of many research groups worldwide during the last decade, mostly driven by the high prospects for applications for science studies (e.g. ultrafast radiography, or prompt heating of dense matter) and society (for medical applications). Compared to ion beams produced by conventional accelerators, the beams produced by intense lasers have been shown to have exceptional properties like extreme brightness, short burst duration and high laminarity. For example, for proton energies above 10 MeV, the transverse (resp. longitudinal) emittance is <0.004 mm m rad (resp. <10-4 eV s), i.e. at least 100-fold (resp. 104-fold) better than conventional accelerator beams. However, their spectral cut-off, although high, is still far from the one reached by conventional accelerators, the beams are divergent (20° typical divergence at the source), and the momentum spectrum of the ions is in general broadband.

  16. Temperature measurements during high flux ion beam irradiations

    DOE PAGES

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

    2016-02-16

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

  17. An Improved Green's Function for Ion Beam Transport

    NASA Technical Reports Server (NTRS)

    Tweed, J.; Wilson, J. W.; Tripathi, R. K.

    2003-01-01

    Ion beam transport theory allows testing of material transmission properties in the laboratory environment generated by particle accelerators. This is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are the main emphasis of the present work. In consequence, an analytic solution of the linear Boltzmann equation is pursued in the form of a Green's function allowing flexibility in application to a broad range of boundary value problems. It has been established that simple solutions can be found for the high charge and energy (HZE) by ignoring nuclear energy downshifts and dispersion. Such solutions were found to be supported by experimental evidence with HZE ion beams when multiple scattering was added. Lacking from the prior solutions were range and energy straggling and energy downshift with dispersion associated with nuclear events. Recently, we have found global solutions including these effects providing a broader class of HZE ion solutions.

  18. Advanced techniques for characterization of ion beam modified materials

    DOE PAGES

    Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; Kluth, Patrick; Tuomisto, Filip

    2014-10-30

    Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiationmore » effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.« less

  19. Large areas elemental mapping by ion beam analysis techniques

    NASA Astrophysics Data System (ADS)

    Silva, T. F.; Rodrigues, C. L.; Curado, J. F.; Allegro, P.; Moro, M. V.; Campos, P. H. O. V.; Santos, S. B.; Kajiya, E. A. M.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.

    2015-07-01

    The external beam line of the Laboratory for Material Analysis with Ion Beams (LAMFI) is a versatile setup for multi-technique analysis. X-ray detectors for Particle Induced X-rays Emission (PIXE) measurements, a Gamma-ray detector for Particle Induced Gamma- ray Emission (PIGE), and a particle detector for scattering analysis, such as Rutherford Backscattering Spectrometry (RBS), were already installed. In this work, we present some results, using a large (60-cm range) XYZ computer controlled sample positioning system, completely developed and build in our laboratory. The XYZ stage was installed at the external beam line and its high spacial resolution (better than 5 μm over the full range) enables positioning the sample with high accuracy and high reproducibility. The combination of a sub-millimeter beam with the large range XYZ robotic stage is being used to produce elemental maps of large areas in samples like paintings, ceramics, stones, fossils, and all sort of samples. Due to its particular characteristics, this is a unique device in the sense of multi-technique analysis of large areas. With the continuous development of the external beam line at LAMFI, coupled to the robotic XYZ stage, it is becoming a robust and reliable option for regular analysis of trace elements (Z > 5) competing with the traditional in-vacuum ion-beam-analysis with the advantage of automatic rastering.

  20. Symmetric neutralized ion beams: Production, acceleration, propagation, and applications

    NASA Astrophysics Data System (ADS)

    Hicks, Nathaniel Kenneth

    This dissertation presents the first integrated experimental, computational, and theoretical research program on symmetric neutralized ion beams. A beam of this type is composed of positive and negative ions having equal charge-to-mass ratios, such that the beam has overall charge neutrality and its constituent ions respond symmetrically to electromagnetic forces. Under the right conditions, these beams may propagate undeflected across transverse magnetic fields due to beam polarization. Such propagation is studied here computationally, using a three-dimensional particle-in-cell code. Also, key theoretical differences between the propagation ability of these beams and that of beams consisting of positive ions and electrons are elucidated. An experimental method of producing a symmetric neutralized ion beam by merging together separate beams of positive and negative ions is demonstrated, and prototype collector hardware to diagnose the composition and energy distribution of the beam is developed. The ability of radio frequency quadrupole accelerators to simultaneously confine and accelerate the positive and negative ions of such a beam is demonstrated computationally and is confirmed experimentally, and a method to reestablish local charge neutrality in the beam after acceleration is conceived and simulated. The favorable scaling of such accelerators to small size and high frequency is illustrated. Finally, applications of the research to magnetic confinement fusion and topics for future study are presented.

  1. Ion Beam Analysis applied to laser-generated plasmas

    NASA Astrophysics Data System (ADS)

    Cutroneo, M.; Macková, A.; Havranek, V.; Malinsky, P.; Torrisi, L.; Kormunda, M.; Barchuk, M.; Ullschmied, J.; Dudzak, R.

    2016-04-01

    This paper presents the research activity on Ion Beam Analysis methods performed at Tandetron Laboratory (LT) of the Institute of Nuclear Physics AS CR, Rez, Czech Republic. Recently, many groups are paying attention to implantation by laser generated plasma. This process allows to insert a controllable amount of energetic ions into the surface layers of different materials modifying the physical and chemical properties of the surface material. Different substrates are implanted by accelerated ions from plasma through terawatt iodine laser, at nominal intensity of 1015 W/cm2, at the PALS Research Infrastructure AS CR, in the Czech Republic. This regime of the laser matter interaction generates, multi-MeV proton beams, and multi-charged ions that are tightly confined in time (hundreds ps) and space (source radius of a few microns). These ion beams have a much lower transverse temperature, a much shorter duration and a much higher current than those obtainable from conventional accelerators. The implementation of protons and ions acceleration driven by ultra-short high intensity lasers is exhibited by adopting suitable irradiation conditions as well as tailored targets. An overview of implanted targets and their morphological and structural characterizations is presented and discussed.

  2. Dose response of alanine detectors irradiated with carbon ion beams

    SciTech Connect

    Herrmann, Rochus; Jaekel, Oliver; Palmans, Hugo; Sharpe, Peter; Bassler, Niels

    2011-04-15

    Purpose: The dose response of the alanine detector shows a dependence on particle energy and type when irradiated with ion beams. The purpose of this study is to investigate the response behavior of the alanine detector in clinical carbon ion beams and compare the results to model predictions. Methods: Alanine detectors have been irradiated with carbon ions with an energy range of 89-400 MeV/u. The relative effectiveness of alanine has been measured in this regime. Pristine and spread out Bragg peak depth-dose curves have been measured with alanine dosimeters. The track structure based alanine response model developed by Hansen and Olsen has been implemented in the Monte Carlo code FLUKA and calculations were compared to experimental results. Results: Calculations of the relative effectiveness deviate less than 5% from the measured values for monoenergetic beams. Measured depth-dose curves deviate from predictions in the peak region, most pronounced at the distal edge of the peak. Conclusions: The used model and its implementation show a good overall agreement for quasimonoenergetic measurements. Deviations in depth-dose measurements are mainly attributed to uncertainties of the detector geometry implemented in the Monte Carlo simulations.

  3. Wrinkled hard skins on polymers created by focused ion beam.

    PubMed

    Moon, Myoung-Woon; Lee, Sang Hoon; Sun, Jeong-Yun; Oh, Kyu Hwan; Vaziri, Ashkan; Hutchinson, John W

    2007-01-23

    A stiff skin forms on surface areas of a flat polydimethylsiloxane (PDMS) upon exposure to focused ion beam (FIB) leading to ordered surface wrinkles. By controlling the FIB fluence and area of exposure of the PDMS, one can create a variety of patterns in the wavelengths in the micrometer to submicrometer range, from simple one-dimensional wrinkles to peculiar and complex hierarchical nested wrinkles. Examination of the chemical composition of the exposed PDMS reveals that the stiff skin resembles amorphous silica. Moreover, upon formation, the stiff skin tends to expand in the direction perpendicular to the direction of ion beam irradiation. The consequent mismatch strain between the stiff skin and the PDMS substrate buckles the skin, forming the wrinkle patterns. The induced strains in the stiff skin are estimated by measuring the surface length in the buckled state. Estimates of the thickness and stiffness of the stiffened surface layer are estimated by using the theory for buckled films on compliant substrates. The method provides an effective and inexpensive technique to create wrinkled hard skin patterns on surfaces of polymers for various applications.

  4. Cryo-focused-ion-beam applications in structural biology.

    PubMed

    Rigort, Alexander; Plitzko, Jürgen M

    2015-09-01

    The ability to precisely control the preparation of biological samples for investigations by electron cryo-microscopy is becoming increasingly important for ultrastructural imaging in biology. Precision machining instruments such as the focused ion beam microscope (FIB) were originally developed for applications in materials science. However, today we witness a growing use of these tools in the life sciences mainly due to their versatility, since they can be used both as manipulation and as imaging devices, when complemented with a scanning electron microscope (SEM). The advent of cryo-preparation equipment and accessories made it possible to pursue work on frozen-hydrated biological specimens with these two beam (FIB/SEM) instruments. In structural biology, the cryo-FIB can be used to site-specifically thin vitrified specimens for transmission electron microscopy (TEM) and tomography. Having control over the specimen thickness is a decisive factor for TEM imaging, as the thickness of the object under scrutiny determines the attainable resolution. Besides its use for TEM preparation, the FIB/SEM microscope can be additionally used to obtain three-dimensional volumetric data from biological specimens. The unique combination of an imaging and precision manipulation tool allows sequentially removing material with the ion beam and imaging the milled block faces by scanning with the electron beam, an approach known as FIB/SEM tomography. This review covers both fields of cryo-FIB applications: specimen preparation for TEM cryo-tomography and volume imaging by cryo-FIB/SEM tomography.

  5. Focused ion beam milling of microchannels in lithium niobate

    PubMed Central

    Sridhar, Manoj; Maurya, Devendra K.; Friend, James R.; Yeo, Leslie Y.

    2012-01-01

    We present experimental and simulation results for focused ion beam (FIB) milling of microchannels in lithium niobate in this paper. We investigate two different cuts of lithium niobate, Y- and Z-cuts, and observe that the experimental material removal rate in the FIB for both Y-cut and Z-cut samples was 0.3 μm3/nC, roughly two times greater than the material removal rate previously reported in the literature but in good agreement with the value we obtain from stopping and range of ions in matter (SRIM) simulations. Further, we investigate the FIB milling rate and resultant cross-sectional profile of microchannels at various ion beam currents and find that the milling rate decreases as a function of ion dose and correspondingly, the cross-sectional profiles change from rectangular to V-shaped. This indicates that material redeposition plays an important role at high ion dose or equivalently, high aspect ratio. We find that the experimental material removal rate decreases as a function of aspect ratio of the milled structures, in good agreement with our simulation results at low aspect ratio and in good agreement with the material removal rates previously reported in the literature at high aspect ratios. Our results show that it is indeed easier than previously assumed to fabricate nanochannels with low aspect ratio directly on lithium niobate using the FIB milling technique. PMID:22662086

  6. Highly charged ion beam applied to lithography technique.

    PubMed

    Momota, Sadao; Nojiri, Yoichi; Taniguchi, Jun; Miyamoto, Iwao; Morita, Noboru; Kawasegi, Noritaka

    2008-02-01

    In various fields of nanotechnology, the importance of nanoscale three-dimensional (3D) structures is increasing. In order to develop an efficient process to fabricate nanoscale 3D structures, we have applied highly charged ion (HCI) beams to the ion-beam lithography (IBL) technique. Ar-ion beams with various charge states (1+ to 9+) were applied to fabricate spin on glass (SOG) and Si by means of the IBL technique. The Ar ions were prepared by a facility built at Kochi University of Technology, which includes an electron cyclotron resonance ion source (NANOGAN, 10 GHz). IBL fabrication was performed as a function of not only the charge state but also the energy and the dose of Ar ions. The present results show that the application of an Ar(9+) beam reduces the etching time for SOG and enhances the etching depth compared with those observed with Ar ions in lower charged states. Considering the high-energy deposition of HCI at a surface, the former phenomena can be understood consistently. Also, the latter phenomena can be understood based on anomalously deep structural changes, which are remarkable for glasses. Furthermore, it has also been shown that the etching depth can be easily controlled with the kinetic energy of the Ar ions. These results show the possibilities of the IBL technique with HCI beams in the field of nanoscale 3D fabrication. PMID:18315242

  7. Ion Beam Plasma Interactions in the ASTRAL Helicon Plasma Source.

    NASA Astrophysics Data System (ADS)

    Boivin, R. F.; Kesterson, A.; Kamar, O.; Lin, Y.; Munoz, J.; Wang, X.

    2008-11-01

    A 100 KeV NEC duoplasmatron is used to produce an energetic ion beam (10 KeV < E < 100 KeV). The beam is sent through plasmas produced by the ASTRAL helicon plasma source. The beam current and beam size are measured by a device combining Retarding Field Analyzer (RFA) and Faraday Cup (FC) features. ASTRAL produces bright intense He/Ne/Ar plasmas with the following parameters: ne = 1E11 -- 1E13 cm-3 and Te = 2 - 10 eV, B-field < 1.3 kGauss, rf power <= 2 kWatt. RF compensated Langmuir probes are used to measure Te and ne. Depending on the ion beam energy and the ratio of beam density over plasma density different wave instabilities will be generated within the plasmas. A real-time spectrum analyzer will be used to identify the wave instabilities and their evolution in the plasma. We will present early experimental results together with some preliminary theoretical simulation using 2D and 3D hybrid simulation codes. In these codes, ions are treated as fully kinetic particles while electrons are treated as a fluid. Both species are moving in a self-consistent electromagnetic field.

  8. Optical studies of ion-beam synthesized metal alloy nanoparticles

    SciTech Connect

    Magudapathy, P. Srivatsava, S. K.; Gangopadhyay, P.; Amirthapandian, S.; Sairam, T. N.; Panigrahi, B. K.

    2015-06-24

    Au{sub x}Ag{sub 1-x} alloy nanoparticles with tunable surface plasmon resonance (SPR) have been synthesized on a silica glass substrate. A small Au foil on an Ag foil is irradiated as target substrates such that ion beam falls on both Ag foil and Au foils. Silica slides are kept at an angle ∼45° with respect to the metallic foils. While irradiating the metallic foils with 100 keV Ar{sup +} ions, sputtered Au and Ag atoms get deposited on the silica-glass. In this configuration the foils have been irradiated by Ar{sup +} ions to various fluences at room temperature and the sputtered species are collected on silica slides. Formation of Au{sub x}Ag{sub 1-x} nanoparticles has been confirmed from the optical absorption measurements. With respect to the exposure area of Au and Ag foils to the ion beam, the SPR peak position varies from 450 to 500 nm. Green photoluminescence has been observed from these alloy metal nanoparticles.

  9. Dosimetric precision of an ion beam tracking system

    PubMed Central

    2010-01-01

    Background Scanned ion beam therapy of intra-fractionally moving tumors requires motion mitigation. GSI proposed beam tracking and performed several experimental studies to analyse the dosimetric precision of the system for scanned carbon beams. Methods A beam tracking system has been developed and integrated in the scanned carbon ion beam therapy unit at GSI. The system adapts pencil beam positions and beam energy according to target motion. Motion compensation performance of the beam tracking system was assessed by measurements with radiographic films, a range telescope, a 3D array of 24 ionization chambers, and cell samples for biological dosimetry. Measurements were performed for stationary detectors and moving detectors using the beam tracking system. Results All detector systems showed comparable data for a moving setup when using beam tracking and the corresponding stationary setup. Within the target volume the mean relative differences of ionization chamber measurements were 0.3% (1.5% standard deviation, 3.7% maximum). Film responses demonstrated preserved lateral dose gradients. Measurements with the range telescope showed agreement of Bragg peak depth under motion induced range variations. Cell survival experiments showed a mean relative difference of -5% (-3%) between measurements and calculations within the target volume for beam tracking (stationary) measurements. Conclusions The beam tracking system has been successfully integrated. Full functionality has been validated dosimetrically in experiments with several detector types including biological cell systems. PMID:20591160

  10. A merging preaccelerator for high current H - ion beams

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Miyamoto, K.; Mizuno, M.; Okumura, Y.; Ohara, Y.; Ackerman, G. D.; Chan, C. F.; Cooper, W. S.; Kwan, J. W.; Vella, M. C.

    1995-07-01

    The high power ion beams used in the next generation thermonuclear fusion reactors require high current negative ion beams accelerated to high energy, with high efficiency. One way to meet these requirements is to merge multiple low current density H- beamlets into a single high current beam. The feasibility of a high current merging preaccelerator was demonstrated in this experiment by merging 19 beamlets of H- ions distributed over a circular area 80 mm in diameter from a Japan Atomic Energy Research Institute negative ion source. H- ions were extracted at a current density exceeding 10 mA/cm2 at the ion source which operates at 0.13 Pa (1 mTorr), with a low arc power density (70 V×250 A). Spherically curved grids (with built-in magnetic electron suppression) were used in the preaccelerator to focus the extracted beamlets into a single 104 mA, 100 keV beam. The merged beam has a diameter of 23 mm and a converging angle of ±30 mrad at the beam envelope. The rms emittance of the 104 mA merging beam was 1.00 π mrad cm, which is a condition acceptable to the electrostatic quadropole accelerator for further acceleration.

  11. Focused ion beam fabrication of boron-doped diamond ultramicroelectrodes.

    PubMed

    Hu, Jingping; Holt, Katherine B; Foord, John S

    2009-07-15

    The fabrication of ultramicroelectrodes (UMEs) for analytical electrochemical applications has been explored, using boron-doped diamond as the active electrode material in an insulating coating formed by deposition of electrophoretic paint. Because of the rough nature of the diamond film, the property of such coatings that is normally exploited in the fabrication of UMEs, namely the tendency to retract automatically from sharp protrusions, cannot be used in the present instance. Instead focused ion beam (FIB) sputtering was employed to controllably produce UMEs with well-defined geometry, critical dimension of a few micrometers, and very thin insulating coatings. If the FIB machining is carried out at normal incidence to the diamond electrode surface, significant ion beam damage reduces the yield of successful electrodes. However, if a parallel machining geometry is employed, high yields of ultramicroelectrodes with a flat disk geometry can be obtained very reliably. The electrochemical properties of diamond UMEs are characterized. They show much lower background currents than the equivalent Pt or carbon fiber electrodes but more varied electrochemical response than macroscopic diamond electrodes. PMID:19545137

  12. An improved Green's function for ion beam transport.

    PubMed

    Tweed, J; Wilson, J W; Tripathi, R K

    2004-01-01

    Ion beam transport theory allows testing of material transmission properties in the laboratory environment generated by particle accelerators. This is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are the main emphasis of the present work. In consequence, an analytic solution of the linear Boltzmann equation is pursued in the form of a Green's function allowing flexibility in application to a broad range of boundary value problems. It has been established that simple solutions can be found for high charge and energy (HZE) ions by ignoring nuclear energy downshifts and dispersion. Such solutions were found to be supported by experimental evidence with HZE ion beams when multiple scattering was added. Lacking from the prior solutions were range and energy straggling and energy downshift with dispersion associated with nuclear events. Recently, we have found global solutions including these effects providing a broader class of HZE ion solutions.

  13. Development of a radioactive ion beam test stand at LBNL

    SciTech Connect

    Burke, J.; Freedman, S.J.; Fujikawa, B.; Gough, R.A.; Lyneis, C.M.; Vetter, P.; Wutte, D.; Xie, Z.Q.

    1998-10-05

    For the on-line production of a {sup 14}O{sup +} ion beam, an integrated target--transfer line ion source system is now under development at LBNL. {sup 14}O is produced in the form of CO in a high temperature carbon target using a 20 MeV {sup 3}He beam from the LBNL 88'' Cyclotron via the reaction {sup 12}C({sup 3}He,n){sup 14}O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O{sub 2} and CO are presented. Ionization efficiencies of 28% for Ar{sup +}, 1% for CO, 0.7% for O{sup +}, 0.33 for C{sup +} have been measured.

  14. Fast fall-time ion beam in neutron generators

    SciTech Connect

    Ji, Q.; Kwan, J.; Regis, M.; Wu, Y.; Wilde, S.B.; Wallig, J.

    2008-08-10

    Ion beam with a fast fall time is useful in building neutron generators for the application of detecting hidden, gamma-shielded SNM using differential die-away (DDA) technique. Typically a fall time of less than 1 {micro}s can't be achieved by just turning off the power to the ion source due to the slow decay of plasma density (partly determined by the fall time of the RF power in the circuit). In this paper, we discuss the method of using an array of mini-apertures (instead of one large aperture beam) such that gating the beamlets can be done with low voltage and a small gap. This geometry minimizes the problem of voltage breakdown as well as reducing the time of flight to produce fast gating. We have designed and fabricated an array of 16 apertures (4 x 4) for a beam extraction experiment. Using a gating voltage of 1400 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is less than 1 {micro}s at various beam energies ranging between 400 eV to 800 eV. Usually merging an array of beamlets suffers the loss of beam brightness, i.e., emittance growth, but that is not an important issue for neutron source applications.

  15. Shaping of Au nanoparticles embedded in various layered structures by swift heavy ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Dawi, E. A.; ArnoldBik, W. M.; Ackermann, R.; Habraken, F. H. P. M.

    2016-10-01

    We present a novel method to extend the ion-beam induced shaping of metallic nanoparticles in various layered structures. Monodisperse Au nanoparticles having mean diameter of 30 nm and their ion-shaping process is investigated for a limited number of experimental conditions. Au nanoparticles were embedded within a single plane in various layered structures of silicon nitride films (Si3N4), combinations of oxide-nitride films (SiO2-Si3N4) and amorphous silicon films (a-Si) and have been sequentially irradiated at 300 K at normal incidence with 50 and 25 MeV Ag ions, respectively. Under irradiation with heavy Ag ions and with sequential increase of the irradiation fluence, the evolution of the Au peak derived from the Rutherford Backscattering Spectrometry show broadening in Au peak, which indicates that the Au becomes distributed over a larger depth region, indicative of the elongation of the nanoparticles. The latter is observed almost for every layer structure investigated except for Au nanoparticles embedded in pure a-Si matrix. The largest elongation rate at all fluences is found for the Au nanoparticles encapsulated in pure Si3N4 films. For all irradiation energy applied, we again demonstrate the existence of both threshold and saturation fluences for the elongation effects mentioned.

  16. Control of secondary electrons from ion beam impact using a positive potential electrode

    NASA Astrophysics Data System (ADS)

    Crowley, T. P.; Demers, D. R.; Fimognari, P. J.

    2016-11-01

    Secondary electrons emitted when an ion beam impacts a detector can amplify the ion beam signal, but also introduce errors if electrons from one detector propagate to another. A potassium ion beam and a detector comprised of ten impact wires, four split-plates, and a pair of biased electrodes were used to demonstrate that a low-voltage, positive electrode can be used to maintain the beneficial amplification effect while greatly reducing the error introduced from the electrons traveling between detector elements.

  17. Beam-deposited platinum as versatile catalyst for bottom-up silicon nanowire synthesis

    SciTech Connect

    Hibst, N.; Strehle, S.; Knittel, P.; Kranz, C.; Mizaikoff, B.

    2014-10-13

    The controlled localized bottom-up synthesis of silicon nanowires on arbitrarily shaped surfaces is still a persisting challenge for functional device assembly. In order to address this issue, electron beam and focused ion beam-assisted catalyst deposition have been investigated with respect to platinum expected to form a PtSi alloy catalyst for a subsequent bottom-up nanowire synthesis. The effective implementation of pure platinum nanoparticles or thin films for silicon nanowire growth has been demonstrated recently. Beam-deposited platinum contains significant quantities of amorphous carbon due to the organic precursor and gallium ions for a focused ion beam-based deposition process. Nevertheless, silicon nanowires could be grown on various substrates regardless of the platinum purity. Additionally, p-type doping could be realized with diborane whereas n-type doping suppressed a nanowire growth. The rational utilization of this beam-assisted approach enables us to control the localized synthesis of single silicon nanowires at planar surfaces but succeeded also in single nanowire growth at the three-dimensional apex of an atomic force microscopy tip. Therefore, this catalyst deposition method appears to be a unique extension of current technologies to assemble complex nanowire-based devices.

  18. Ion beam sputtering of fluoropolymers. [etching polymer films and target surfaces

    NASA Technical Reports Server (NTRS)

    Sovey, J. S.

    1978-01-01

    Ion beam sputter processing rates as well as pertinent characteristics of etched targets and films are described. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Sputter target and film characteristics documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs are included.

  19. Effect of using stencil masks made by focused ion beam milling on permalloy (Ni81Fe19) nanostructures.

    PubMed

    Bates, J R; Miyahara, Y; Burgess, J A J; Iglesias-Freire, O; Grütter, P

    2013-03-22

    Focused ion beam (FIB) milling is a common fabrication technique to make nanostencil masks which has the unintended consequence of gallium ion implantation surrounding milled features in silicon nitride membranes. We observe major changes in film structure, chemical composition, and magnetic behaviour of permalloy nanostructures deposited by electron beam evaporation using silicon nitride stencil masks made by a FIB as compared to stencil masks made by regular lithography techniques. We characterize the stenciled structures and both types of masks using transmission electron microscopy, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy, magnetic force microscopy and kelvin probe force microscopy. All these techniques demonstrate distinct differences at a length scale of a 1-100 nm for the structures made using stencil mask fabricated using a FIB. The origin of these differences seems to be related to the presence of implanted ions, a detailed understanding of the mechanism however remains to be developed. PMID:23449320

  20. Fabrication of porous silicon by metal-assisted etching using highly ordered gold nanoparticle arrays

    NASA Astrophysics Data System (ADS)

    Scheeler, Sebastian P.; Ullrich, Simon; Kudera, Stefan; Pacholski, Claudia

    2012-08-01

    A simple method for the fabrication of porous silicon (Si) by metal-assisted etching was developed using gold nanoparticles as catalytic sites. The etching masks were prepared by spin-coating of colloidal gold nanoparticles onto Si. An appropriate functionalization of the gold nanoparticle surface prior to the deposition step enabled the formation of quasi-hexagonally ordered arrays by self-assembly which were translated into an array of pores by subsequent etching in HF solution containing H2O2. The quality of the pattern transfer depended on the chosen preparation conditions for the gold nanoparticle etching mask. The influence of the Si surface properties was investigated by using either hydrophilic or hydrophobic Si substrates resulting from piranha solution or HF treatment, respectively. The polymer-coated gold nanoparticles had to be thermally treated in order to provide a direct contact at the metal/Si interface which is required for the following metal-assisted etching. Plasma treatment as well as flame annealing was successfully applied. The best results were obtained for Si substrates which were flame annealed in order to remove the polymer matrix - independent of the substrate surface properties prior to spin-coating (hydrophilic or hydrophobic). The presented method opens up new resources for the fabrication of porous silicon by metal-assisted etching. Here, a vast variety of metal nanoparticles accessible by well-established wet-chemical synthesis can be employed for the fabrication of the etching masks.