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Sample records for beam loss ion

  1. Neutral Beam Ion Loss Modeling for NSTX

    SciTech Connect

    D. Mikkelsen; D.S. Darrow; L. Grisham; R. Akers; S. Kaye

    1999-06-01

    A numerical model, EIGOL, has been developed to calculate the loss rate of neutral beam ions from NSTX and the resultant power density on the plasma facing components. This model follows the full gyro-orbit of the beam ions, which can be a significant fraction of the minor radius. It also includes the three-dimensional structure of the plasma facing components inside NSTX. Beam ion losses from two plasma conditions have been compared: {beta} = 23%, q{sub 0} = 0.8, and {beta} = 40%, q{sub 0} = 2.6. Global losses are computed to be 4% and 19%, respectively, and the power density on the rf antenna is near the maximum tolerable levels in the latter case.

  2. Neutral Beam Ion Loss Modelling for NSTX

    NASA Astrophysics Data System (ADS)

    Darrow, D. S.; Akers, R.; Kaye, S. M.; Mikkelsen, D. R.

    1999-11-01

    The loss of 80 keV D neutral beam ions to the walls has been modeled for a range of plasma conditions in NSTX using the EIGOL code[1]. Initial results of the code are in reasonable agreement with those from the LOCUST code[2]. Both codes predict loss fractions of 20% for a discharge with β_T=40% and q_0=2.6. Losses are strongly concentrated on the front face and edges of the high-harmonic fast wave antenna as it projects farther inward than other internal structures at the midplane. The edges of the passive stabilizer plates near the midplane are also subject to a large flux of lost beam ions under some conditions. The dependence of the loss upon the plasma density profile, I_p, and BT will be presented. [1] D. S. Darrow, et al., in Proceedings of the 26th EPS Conference on Controlled Fusion and Plasma Physics, Maastricht, The Netherlands, 14-18 June 1999. [2] R. Akers, et al., ibid.

  3. Measurements of Beam Ion Loss from the Compact Helical System

    SciTech Connect

    D. S. Darrow, M. Isobe, Takashi Kondo, M. Sasao, and the CHS Group National Institute for Fusion Science, Toki, Gifu, Japan

    2010-02-03

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  4. MHD Induced Neutral Beam Ion Loss from NSTX Plasmas

    SciTech Connect

    D.S. Darrow, E.D. Fredrickson, N.N. Gorelenkov, A.L. Roquemore, and K. Shinohara

    2007-12-13

    Bursts of ~60 kHz activity on Mirnov coils occur frequently in NSTX plasmas and these are accompanied by bursts of neutral beam ion loss over a range in pitch angles. These losses have been measured with a scintillator type loss probe imaged with a high speed (>10,000 frames/s) video camera, giving the evolution of the energy and pitch angle distributions of the lost neutral beam ions over the course of the events. The instability occurs below the TAE frequency in NSTX (~100 kHz) in high beta plasmas and may be a beta driven Alfvén acoustic (BAAE) mode.

  5. Losses of ion energy in the multicomponent beam

    NASA Astrophysics Data System (ADS)

    Gasanov, Ilkham S.; Gurbanov, Ilgar I.; Akbarov, Elchin M.

    2015-03-01

    Energy losses of near axis ions and decreases in ion current density in the center of a beam were observed in a liquid metal source operating under a charged nanodroplets (In, Sn, Au, Ge) generation regime. In experiments, nanodroplets with the sizes of 2-20 nanometers and a characteristic specific charge of 5 × 104 C/kg were revealed. Energy spectra of ions were defined by means of the filter of speeds with cross-section static electromagnetic fields. A reduction of 4% of the In+ ions energy was observed under the conditions of the curried out measurements. The stream of nanoparticles, in contrast to an ion beam, has a small radial divergence; outside of this stream, change of ion speeds is not observed. Energy losses of ions occur during their flight through small nanoparticles. Penetration depth of the accelerated ions in liquid indium is estimated within the framework of the Lindhard-Scharff-Schiott model. Similar interaction between components occurs in ion-beam systems of complex composition where there is a relative movement of various charged particles.

  6. Beam loss ion chamber system upgrade for experimental halls

    SciTech Connect

    D. Dotson; D. Seidman

    2005-08-01

    The Beam loss Ion Chamber System (BLICS) was developed to protect Jefferson Labs transport lines, targets and beam dumps from a catastrophic ''burn through''. Range changes and testing was accomplished manually requiring the experiment to be shut down. The new upgraded system is based around an ''off the shelf'' Programmable Logic Controller located in a single control box supporting up to ten individual detectors. All functions that formerly required an entry into the experimental hall and manual adjustment can be accomplished from the Machine Control Center (MCC). A further innovation was the addition of a High Voltage ''Brick'' at the detector location. A single cable supplies the required voltage for the Brick and a return line for the ion chamber signal. The read back screens display range, trip point, and accumulated dose for each location. The new system is very cost effective and significantly reduces the amount of lost experimental time.

  7. Beam Loss Ion Chamber System Upgrade for Experimental Halls

    SciTech Connect

    D.W. Dotson; D.J. Seidman

    2005-05-16

    The Beam loss Ion Chamber System (BLICS) was developed to protect Jefferson Labs transport lines, targets and beam dumps from a catastrophic ''burn through''. Range changes and testing was accomplished manually requiring the experiment to be shut down. The new upgraded system is based around an ''off the shelf'' Programmable Logic Controller located in a single control box supporting up to ten individual detectors. All functions that formerly required an entry into the experimental hall and manual adjustment can be accomplished from the Machine Control Center (MCC). A further innovation was the addition of a High Voltage ''Brick'' at the detector location. A single cable supplies the required voltage for the Brick and a return line for the ion chamber signal. The read back screens display range, trip point, and accumulated dose for each location. The new system is very cost effective and significantly reduces the amount of lost experimental time.

  8. Multiple-electron losses in uranium ion beams in heavy ion synchrotrons

    NASA Astrophysics Data System (ADS)

    Bozyk, L.; Chill, F.; Litsarev, M. S.; Tolstikhina, I. Yu.; Shevelko, V. P.

    2016-04-01

    Charge changing processes as the result of collisions with residual gas particles are the main cause of beam loss in high energy medium charge state heavy ion beams. To investigate the magnitude of this effect for heavy ion synchrotrons like the planned SIS100 at GSI, the multiple-electron and the total electron-loss cross sections are calculated for Uq+ ions, q = 10, 28, 40, 73, colliding with typical gas components H2, He, C, N2, O2, and Ar at ion energies E = 1 MeV/u-10 GeV/u. The total electron-capture cross sections for U28+ and U73+ ions interacting with these gases are also calculated. Most of these cross sections are new and presented for the first time. Calculated charge-changing cross sections are used to determine the ion-beam lifetimes τ for U28+ ions which agree well with the recently measured values at SIS18/GSI in the energy range E = 10-200 MeV/u. Using simulations made by the StrahlSim code with the reference ion U28+, it is found that in SIS100 the beam loss caused by single and multiple electron losses has only little impact on the residual gas density due to the high efficiency of the ion catcher system.

  9. Modelling of Ion Bernstein Wave-Driven Deuterium Beam Ion Losses in TFTR.

    NASA Astrophysics Data System (ADS)

    Heeter, R. F.; Fisch, N. J.; Darrow, D. S.; Herrmann, M. C.; Majeski, R.

    1996-11-01

    A 1-D velocity-space diffusion/drag model is used to understand MeV-range deuterium beam ion losses driven by mode-converted Ion Bernstein Waves in TFTR. [D. Darrow et. al., this conference.] Simulated losses provide insight into the nature of the loss process and an estimation of the velocity diffusion coefficent. Implications for channeling of alpha particle energy to fuel ions are discussed. [Work supported by U.S. DoE contract DE-AC02-76-CH03073; two of the authors (RFH and MCH) also acknowledge the support of the Fannie and John Hertz Foundation.

  10. A new beam loss detector for low-energy proton and heavy-ion accelerators

    NASA Astrophysics Data System (ADS)

    Liu, Zhengzheng; Crisp, Jenna; Russo, Tom; Webber, Robert; Zhang, Yan

    2014-12-01

    The Facility for Rare Isotope Beams (FRIB) to be constructed at Michigan State University shall deliver a continuous, 400 kW heavy ion beam to the isotope production target. This beam is capable of inflicting serious damage on accelerator components, e.g. superconducting RF accelerating cavities. A Beam Loss Monitoring (BLM) System is essential for detecting beam loss with sufficient sensitivity and promptness to inform the machine protection system (MPS) and operations personnel of impending dangerous losses. Radiation transport simulations reveal shortcomings in the use of ionization chambers for the detection of beam losses in low-energy, heavy-ion accelerators. Radiation cross-talk effects due to the folded geometry of the FRIB LINAC pose further complications to locating specific points of beam loss. We propose a newly developed device, named the Loss Monitor Ring (LMR1

  11. Residual activity induced by heavy ions and beam-loss criteria for heavy-ion accelerators

    NASA Astrophysics Data System (ADS)

    Strašík, I.; Mustafin, E.; Pavlovič, M.

    2010-07-01

    The paper presents results of FLUKA simulations of the residual activity induced by heavy ions in two target configurations representing: (1) a beam pipe of an accelerator and (2) a bulky accelerator structure like a magnet yoke or a coil. The target materials were stainless steel and copper representing the most common construction materials used for basic accelerator components. For these two materials, the inventory of the induced isotopes depends mainly on the target material and much less on the projectile species. Time evolution of the induced activity can be described by means of a generic curve that is independent from the projectile mass. Dependence of the induced residual activity on selected ion beam parameters was studied. The main goal of the study was establishing a scaling law expanding the existing proton beam-loss tolerance to heavy-ion beams. This scaling law enables specifying beam-loss criteria for projectile species from proton up to uranium at energies from 200MeV/u up to 1GeV/u.

  12. Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance

    SciTech Connect

    Reginald M. Ronningen; Igor Remec

    2010-09-11

    Dose rates from accelerator components activated by 1 W/m beam losses are obtained semiempirically for a 1 GeV proton beam and by use of Monte Carlo transport codes for the proton beam and for 777 MeV/u 3He, 500 MeV/u 48Ca, 86Kr, 136Xe, and 400 MeV/u 238U ions. The dose rate obtained by the semi-empirical method, 0.99 mSv/h (99 mrem/h) at 30 cm, 4 h after 100 d irradiation by a 1-GeV proton beam, is consistent with studies at several accelerator facilities and with adopted hands-on maintenance dose rate limits. Monte Carlo simulations verify this result for protons and extend studies to heavy ion beam losses in drift-tube linac and superconducting linac accelerating structures. The studies indicate that the 1 W/m limit imposed on uncontrolled beam losses for high-energy proton beams might be relaxed for heavy ion beams. These studies further suggest that using the ratio of neutrons produced by a heavy ion beam to neutrons produced by a proton beam along with the dose rate from the proton beam (for thin-target scenarios) should allow an estimate of the dose rates expected from heavy ion beam losses.

  13. The role of electronic energy loss in ion beam modification of materials

    SciTech Connect

    Weber, William J.; Duffy, Dorothy M.; Thome, Lionel; Zhang, Yanwen

    2014-10-05

    The interaction of energetic ions with solids results in energy loss to both atomic nuclei and electrons in the solid. In this article, recent advances in understanding and modeling the additive and competitive effects of nuclear and electronic energy loss on the response of materials to ion irradiation are reviewed. Experimental methods and large-scale atomistic simulations are used to study the separate and combined effects of nuclear and electronic energy loss on ion beam modification of materials. The results demonstrate that nuclear and electronic energy loss can lead to additive effects on irradiation damage production in some materials; while in other materials, the competitive effects of electronic energy loss leads to recovery of damage induced by elastic collision cascades. Lastly, these results have significant implications for ion beam modification of materials, non-thermal recovery of ion implantation damage, and the response of materials to extreme radiation environments.

  14. The role of electronic energy loss in ion beam modification of materials

    DOE PAGESBeta

    Weber, William J.; Duffy, Dorothy M.; Thome, Lionel; Zhang, Yanwen

    2014-10-05

    The interaction of energetic ions with solids results in energy loss to both atomic nuclei and electrons in the solid. In this article, recent advances in understanding and modeling the additive and competitive effects of nuclear and electronic energy loss on the response of materials to ion irradiation are reviewed. Experimental methods and large-scale atomistic simulations are used to study the separate and combined effects of nuclear and electronic energy loss on ion beam modification of materials. The results demonstrate that nuclear and electronic energy loss can lead to additive effects on irradiation damage production in some materials; while inmore » other materials, the competitive effects of electronic energy loss leads to recovery of damage induced by elastic collision cascades. Lastly, these results have significant implications for ion beam modification of materials, non-thermal recovery of ion implantation damage, and the response of materials to extreme radiation environments.« less

  15. Stochastic Orbit Loss of Neutral Beam Ions From NSTX Due to Toroidal Alfven Eigenmode Avalanches

    SciTech Connect

    Darrow, D S; Fredrickson, E D; Gorelenkov, N N; Gorelenkova, M; Kubota, S; Medley, S S; Podesta, M; Shi, L

    2012-07-11

    Short toroidal Alfven eigenmode (TAE) avalanche bursts in the National Spherical Torus Experiment (NSTX) cause a drop in the neutron rate and sometimes a loss of neutral beam ions at or near the full injection energy over an extended range of pitch angles. The simultaneous loss of wide ranges of pitch angle suggests stochastic transport of the beam ions occurs. When beam ion orbits are followed with a guiding center code that incorporates plasma's magnetic equilibrium plus the measured modes, the predicted ranges of lost pitch angle are similar to those seen in the experiment, with distinct populations of trapped and passing orbits lost. These correspond to domains where the stochasticity extends in the orbit phase space from the region of beam ion deposition to the loss boundary.

  16. Beam loss studies in high-intensity heavy-ion linacs

    NASA Astrophysics Data System (ADS)

    Ostroumov, P. N.; Aseev, V. N.; Mustapha, B.

    2004-09-01

    The proposed Rare Isotope Accelerator (RIA) Facility, an innovative exotic-beam facility for the production of high-quality beams of short-lived isotopes, consists of a fully superconducting 1.4GV driver linac and a 140MV postaccelerator. To produce sufficient intensities of secondary beams the driver linac will provide 400kW primary beams of any ion from hydrogen to uranium. Because of the high intensity of the primary beams the beam losses must be minimized to avoid radioactivation of the accelerator equipment. To keep the power deposited by the particles lost on the accelerator structures below 1 W/m, the relative beam losses per unit length should be less than 10-5, especially along the high-energy section of the linac. A new beam dynamics simulation code TRACK has been developed and used for beam loss studies in the RIA driver linac. In the TRACK code, ions are tracked through the three-dimensional electromagnetic fields of every element of the linac starting from the electron cyclotron resonance (ECR) ion source to the production target. The simulation starts with a multicomponent dc ion beam extracted from the ECR. The space charge forces are included in the simulations. They are especially important in the front end of the driver linac. Beam losses are studied by tracking a large number of particles (up to 106) through the whole linac considering all sources of error such us element misalignments, rf field errors, and stripper thickness fluctuations. For each configuration of the linac, multiple sets of error values have been randomly generated and used in the calculations. The results are then combined to calculate important beam parameters, estimate beam losses, and characterize the corresponding linac configuration. To track a large number of particles for a comprehensive number of error sets (up to 500), the code TRACK was parallelized and run on the Jazz computer cluster at ANL.

  17. Observations of neutral beam and ICRF tail ion losses due to Alfven modes in TFTR

    SciTech Connect

    Darrow, D.S.; Zweben, S.J.; Chang, Z.

    1996-04-01

    Fast ion losses resulting from MHD modes at the Alfven frequency, such as the TAE, have been observed in TFTR. The modes have been driven both by neutral beam ions, at low B{sub T}, and by H-minority ICRF tail ions at higher B{sub T}. The measurements indicate that the loss rate varies linearly with the mode amplitude, and that the fast ion losses during the mode activity can be significant, e.g. up to 10% of the input power is lost in the worst case.

  18. Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Hermes, P. D.; Bruce, R.; Jowett, J. M.; Redaelli, S.; Salvachua Ferrando, B.; Valentino, G.; Wollmann, D.

    2016-05-01

    The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which 82+208Pb ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.

  19. Beam loss

    NASA Astrophysics Data System (ADS)

    VanGinneken, A.; Edwards, D.; Harrison, M.

    1989-04-01

    This paper presents results from simulations of beam losses during the operation of a superconducting accelerator. The calculations use a combination of hadron/electromagnetic cascade plus elastic scattering codes with accelerator tracking routines. These calculations have been used in conjunction with the design of the Fermilab Tevatron. First accelerator geometry is described. The rest of the paper discusses a detailed attempt to simulate a fast extraction cycle, essentially in chronological order. Beginning with an unperturbed beam, the simulation generates proton phase-space distributions incident on the electrostatic septum. These interact either elastically or inelastically with the septum wires, and the products of these interactions are traced through the machine. Where these leave the accelerator, energy deposition levels in the magnets are calculated together with the projected response of the beam-loss monitors in this region. Finally, results of the calculation are compared with experimental data. (AIP)

  20. Anomalous Beam-Ion Loss in TFTR Reversed Magnetic Shear Plasmas

    SciTech Connect

    Ruskov, E.; Bell, M.; Budny, R.V.; McCune, D.C.; Medley, S.S.; Redi, M.H.; Scott, S.; Synakowski, E.J.; von Goeler, S.; White, R.B.; Zweben, S.J.

    1999-02-01

    Anomalous beam-ion loss has been observed in an experiment with short tritium beam pulses injected into deuterium-beam-heated Tokamak Fusion Test Reactor plasmas (P{sub NBI}=15 thinspthinspMW) with reversed magnetic shear (RS). Comparisons of the measured total 14thinspthinspMeV neutron emission, the neutron flux along eight radial locations, and the perpendicular plasma stored energy with predictions from an extensive set of TRANSP simulations suggest that about 40{percent} beam power is lost on a time scale much shorter than the tritium beam pulse length {Delta}t=70 thinspthinspms. In contrast with recent results [K. Tobita {ital et al.,} Nucl.thinspthinspFusion {bold 37}, 1583 (1997)] from RS experiments at JT-60U, we were not able to show conclusively that magnetic field ripple is responsible for this anomaly. {copyright} {ital 1999} {ital The American Physical Society}

  1. Anomalous Beam-Ion Loss in TFTR Reversed Magnetic Shear Plasmas

    NASA Astrophysics Data System (ADS)

    Ruskov, E.; Bell, M.; Budny, R. V.; McCune, D. C.; Medley, S. S.; Redi, M. H.; Scott, S.; Synakowski, E. J.; von Goeler, S.; White, R. B.; Zweben, S. J.

    1999-02-01

    Anomalous beam-ion loss has been observed in an experiment with short tritium beam pulses injected into deuterium-beam-heated Tokamak Fusion Test Reactor plasmas ( PNBI = 15 MW) with reversed magnetic shear (RS). Comparisons of the measured total 14 MeV neutron emission, the neutron flux along eight radial locations, and the perpendicular plasma stored energy with predictions from an extensive set of TRANSP simulations suggest that about 40% beam power is lost on a time scale much shorter than the tritium beam pulse length Δt = 70 ms. In contrast with recent results [K. Tobita et al., Nucl. Fusion 37, 1583 (1997)] from RS experiments at JT-60U, we were not able to show conclusively that magnetic field ripple is responsible for this anomaly.

  2. Modeling the response of a fast ion loss detector using orbit tracing techniques in a neutral beam prompt-loss study on the DIII-D tokamak

    SciTech Connect

    Pace, D. C.; Heidbrink, W. W.; Muscatello, C. M.; Zhu, Y. B.; Fisher, R. K.; Van Zeeland, M. A.; Garcia-Munoz, M.; Darrow, D. S.; Nazikian, R.

    2010-10-15

    A numerical model describing the expected measurements of neutral beam prompt-losses by a newly commissioned fast ion loss detector (FILD) in DIII-D is presented. This model incorporates the well understood neutral beam deposition profiles from all eight DIII-D beamlines to construct a prompt-loss source distribution. The full range of detectable ion orbit phase space available to the FILD is used to calculate ion trajectories that overlap with neutral beam injection footprints. Weight functions are applied to account for the level of overlap between these detectable orbits and the spatial and velocity (pitch) properties of ionized beam neutrals. An experimental comparison is performed by firing each neutral beam individually in the presence of a ramping plasma current. Fast ion losses determined from the model are in agreement with measured losses.

  3. Stochastic orbit loss of neutral beam ions from NSTX due to toroidal Alfvén eigenmode avalanches

    SciTech Connect

    Darrow, D. S.; Crocker, N.; Fredrickson, E. D.; Gorelenkov, N. N.; Gorelenkova, M.; Kubota, S.; Medley, S. S.; Podestà, M.; Shi, L.; White, R. B.

    2012-12-17

    Short toroidal Alfvén eigenmode (TAE) avalanche bursts in the National Spherical Torus Experiment (NSTX) cause a drop in the neutron rate and could also cause a loss of neutral beam ions at or near the full injection energy over an extended range of pitch angles. The simultaneous loss of wide ranges of pitch angle suggests stochastic transport of the beam ions takes place. When beam ion orbits are followed with a guiding centre code that incorporates the plasma's magnetic equilibrium plus the measured modes, the predicted ranges of lost pitch angle are like those seen in the experiment, with distinct populations of trapped and passing orbits lost. These correspond to domains where the stochasticity extends in the orbit phase space from the region of beam ion deposition to the loss boundary and the trajectories along which modes may transport particles extend from the deposition volume to the loss boundary.

  4. CEBAF beam loss accounting

    SciTech Connect

    Ursic, R.; Mahoney, K.; Hovater, C.; Hutton, A.; Sinclair, C.

    1995-12-31

    This paper describes the design and implementation of a beam loss accounting system for the CEBAF electron accelerator. This system samples the beam curent throughout the beam path and measures the beam current accurately. Personnel Safety and Machine Protection systems use this system to turn off the beam when hazardous beam losses occur.

  5. Fail-safe ion chamber beam loss monitor system for personnel protection

    NASA Astrophysics Data System (ADS)

    Brown, D.; Plum, M. A.; Browman, A. A.; Macek, R. J.

    1999-01-01

    A fail-safe beam loss monitor system has been designed for use in the Los Alamos Neutron Scattering Center (LANSCE) Radiation Security System (RSS). The latest version (Model III) has been in use since 1991. This system has been carefully designed to protect personnel from large radiation doses caused by errant beam conditions during beam transport. Due to limited shielding between the beam transport lines and occupied areas, personnel can safely occupy these areas only if the beam losses in the transport lines are sufficiently low. Although the usual solution is to increase the bulk shielding between the beam lines and the occupied areas, the physical dimensions of the site do not permit additional shielding to be added. In this paper we will discuss the design and implementation of the fail-safe beam loss monitor system.

  6. Measurement profiles of nano-scale ion beam for optimized radiation energy losses

    NASA Astrophysics Data System (ADS)

    Woo, T. H.; Cho, H. S.

    2011-10-01

    The behavior of charged particles is investigated for nano-scale ion beam therapy using a medical accelerator. Computational work is performed for the Bragg-peak simulation, which is focused on human organ material of pancreas and thyroid. The Results show that the trends of the dose have several different kinds of distributions. Before constructing a heavy ion collider, this study can give us the reliability of the therapeutic effect. Realistic treatment using human organs is calculated in a simple and cost effective manner using the computational code, the Stopping and Range of Ions in Matter 2008 (SRIM 2008). Considering the safety of the therapy, it is suggested to give a patient orient planning of the cancer therapy. The energy losses in ionization and phonon are analyzed, which are the behaviors in the molecular level nano-scopic investigation. The different fluctuations are shown at 150 MeV, where the lowest temperature is found in proton and pancreas case. Finally, the protocol for the radiation therapy is constructed by the simulation in which the procedure for a better therapy is selected. An experimental measurement incorporated with the simulations could be programmed by this protocol.

  7. Prompt Loss of Energetic Ions during Early Neutral Beam Injection in the National Spherical Torus Experiment

    SciTech Connect

    S.S. Medley; D.S. Darrow; D. Liu; A.L. Roquemore

    2005-03-25

    Early neutral-beam injection is used in the National Spherical Torus Experiment (NSTX) to heat the electrons and slow current penetration which keeps q(0) elevated to avoid deleterious MHD activity and at the same time reduces Ohmic flux consumption, all of which aids long-pulse operation. However, the low plasma current (I{sub p} {approx} 0.5 MA) and electron density (n{sub e} {approx} 1 x 10{sup 13} cm{sup -3}) attending early injection lead to elevated orbit and shine through losses. The inherent orbit losses are aggravated by large excursions in the outer gap width during current ramp-up. An investigation of this behavior using various energetic particle diagnostics on NSTX and TRANSP code analysis is presented.

  8. Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam

    NASA Astrophysics Data System (ADS)

    Thomé, Lionel; Debelle, Aurélien; Garrido, Frédérico; Trocellier, Patrick; Serruys, Yves; Velisa, Gihan; Miro, Sandrine

    2013-04-01

    Single and dual-beam irradiations of oxide (c-ZrO2, MgO, Gd2Ti2O7) and carbide (SiC) single crystals were performed to study combined effects of nuclear (Sn) and electronic (Se) energy losses. Rutherford backscattering experiments in channeling conditions show that the Sn/Se cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO2 and Gd2Ti2O7. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative Sn/Se effects may lead to the preservation of the integrity of nuclear devices.

  9. Beam losses from ultra-peripheral nuclear collisions between Pb ions in the Large Hadron Collider and their alleviation

    SciTech Connect

    Bruce, R.; Bocian, D.; Gilardoni, S.; Jowett, J.M.; /CERN

    2009-08-01

    Electromagnetic interactions between colliding heavy ions at the Large Hadron Collider (LHC) at CERN will give rise to localized beam losses that may quench superconducting magnets, apart from contributing significantly to the luminosity decay. To quantify their impact on the operation of the collider, we have used a three-step simulation approach, which consists of optical tracking, a Monte-Carlo shower simulation and a thermal network model of the heat flow inside a magnet. We present simulation results for the case of {sup 208}Pb{sup 82+} ion operation in the LHC, with focus on the alice interaction region, and show that the expected heat load during nominal {sup 208}Pb{sup 82+} operation is 40% above the quench level. This limits the maximum achievable luminosity. Furthermore, we discuss methods of monitoring the losses and possible ways to alleviate their effect.

  10. Mars Express observations of high altitude planetary ion beams and their relation to the "energetic plume" loss channel

    NASA Astrophysics Data System (ADS)

    Liemohn, Michael W.; Johnson, Blake C.; Fränz, Markus; Barabash, Stas

    2014-12-01

    This study presents observational evidence of high-energy (ions >2 keV) beams of planetary ions above Mars' induced magnetospheric boundary (IMB) and relates them with the energetic plume loss channel calculated from numerical models. A systematic search of the Mars Express (MEX) ion data using an orbit filtering criteria is described, using magnetometer data from Mars Global Surveyor (MGS) to determine the solar wind motional electric field (Esw) direction. Two levels of statistical survey are presented, one focused on times when the MEX orbit was directly in line with the Esw and another for all angles between the MEX location and the Esw. For the first study, within the 3 year overlap of MGS and MEX, nine brief intervals were found with clear and unambiguous high-energy O+ observations consistent with the energetic plume loss channel. The second survey used a point-by-point determination of MEX relative to the E-field and contained many thousands of 192 s measurements. This study yielded only a weak indication for an Esw-aligned plume. Furthermore, the y-z components of the weighted average velocities in the bins of this y-z spatial domain survey do not systematically point in the Esw direction. The first survey implies the existence of this plume and shows that its characteristics are seemingly consistent with the expected energy and flight direction from numerical studies; the second study softens the finding and demonstrates that there are many planetary ions beyond the IMB moving in unexpected directions. Several possible explanations for this discrepancy are discussed.

  11. Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam

    SciTech Connect

    Thome, Lionel; Debelle, Aurelien; Garrido, Frederico; Trocellier, Patrick; Serruys, Yves; Miro, Sandrine

    2013-04-08

    Single and dual-beam irradiations of oxide (c-ZrO{sub 2}, MgO, Gd{sub 2}Ti{sub 2}O{sub 7}) and carbide (SiC) single crystals were performed to study combined effects of nuclear (S{sub n}) and electronic (S{sub e}) energy losses. Rutherford backscattering experiments in channeling conditions show that the S{sub n}/S{sub e} cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO{sub 2} and Gd{sub 2}Ti{sub 2}O{sub 7}. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative S{sub n}/S{sub e} effects may lead to the preservation of the integrity of nuclear devices.

  12. Ion Beam Propulsion Study

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

  13. Broad beam ion implanter

    DOEpatents

    Leung, Ka-Ngo

    1996-01-01

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes.

  14. Broad beam ion implanter

    DOEpatents

    Leung, K.N.

    1996-10-08

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes. 6 figs.

  15. Measurement of Absolute Excitation Cross Sections in Highly-Charged Ions Using Electron Energy Loss and Merged Beams

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Smith, Steven J.; Lozano, J.

    2002-01-01

    There is increasing emphasis during this decade on understanding energy balance and phenomena observed in high electron temperature plasmas. The UV spectral return from FUSE, the X-ray spectral return from the HETG on Chandra and the LETGS 011 XMM-Newton are just beginning. Line emissions are almost entirely from highly-charged ions (HCIs) of C, N, 0, Ne, Mg, S, Si, Ca, and Fe. The Constellation-X mission will provide X-ray spectroscopy up to photon energies of 0.12 nm (10 keV) where primary line emitters will be HCIs. A variety of atomic parameters are required to model the stellar and solar plasma. These include cross sections for excitation, ionization, charge-exchange, X-ray emission, direct and indirect recombination, lifetimes and branching ratios, and dependences on l, m mixing by external E and B fields. In almost all cases the atomic quantities are calculated, and few comparisons to experiment have been carried out. Collision strengths and Einstein A-values are required to convert the observed spectral intensities to electron temperatures and densities in the stellar plasma. The JPL electron energy-loss and merged beam approach has been used to measure absolute collision strengths in a number of ions, with critical comparison made to the best available theories.

  16. Fast ion loss diagnostic plans for NSTX

    SciTech Connect

    D. S. Darrow; R. Bell; D. W. Johnson; H. Kugel; J. R. Wilson; F. E. Cecil; R. Maingi; A. Krasilnikov; A. Alekseyev

    2000-06-13

    The prompt loss of neutral beam ions from the National Spherical Torus Experiment (NSTX) is expected to be between 12% and 42% of the total 5 MW of beam power. There may, in addition, be losses of fast ions arising from high harmonic fast wave (HHFW) heating. Most of the lost ions will strike the HHFW antenna or the neutral beam dump. To measure these losses in the 2000 experimental campaign, thermocouples in the antenna, several infrared camera views, and a Faraday cup lost ion probe will be employed. The probe will measure loss of fast ions with E > 1 keV at three radial locations, giving the scrape-off length of the fast ions.

  17. 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.

  18. Ion beam thruster shield

    NASA Technical Reports Server (NTRS)

    Power, J. L. (Inventor)

    1976-01-01

    An ion thruster beam shield is provided that comprises a cylindrical housing that extends downstream from the ion thruster and a plurality of annular vanes which are spaced along the length of the housing, and extend inwardly from the interior wall of the housing. The shield intercepts and stops all charge exchange and beam ions, neutral propellant, and sputter products formed due to the interaction of beam and shield emanating from the ion thruster outside of a fixed conical angle from the thruster axis. Further, the shield prevents the sputter products formed during the operation of the engine from escaping the interior volume of the shield.

  19. 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.

  20. Recovery effects due to the interaction between nuclear and electronic energy losses in SiC irradiated with a dual-ion beam

    NASA Astrophysics Data System (ADS)

    Thomé, Lionel; Velisa, Gihan; Miro, Sandrine; Debelle, Aurélien; Garrido, Frédérico; Sattonnay, Gaël; Mylonas, Stamatis; Trocellier, Patrick; Serruys, Yves

    2015-03-01

    Single and dual-beam ion irradiations of silicon carbide (SiC) were performed to study possible Synergetic effects between Nuclear (Sn) and Electronic (Se) Energy Losses. Results obtained combining Rutherford backscattering in channeling conditions, Raman spectroscopy, and transmission electron microscopy techniques show that dual-beam irradiation of SiC induces a dramatic change in the final sample microstructure with a substantial decrease of radiation damage as compared to single-beam irradiation. Actually, a defective layer containing dislocations is formed upon dual-beam irradiation (Sn&Se), whereas single low-energy irradiation (Sn alone) or even sequential (Sn + Se) irradiations lead to full amorphization. The healing process is ascribed to the electronic excitation arising from the electronic energy loss of swift ions. These results shed new light on the long-standing puzzling problem of the existence of a possible synergy between Sn and Se in ion-irradiation experiments. This work is interesting for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where recovery Sn/Se effects may preserve the integrity of nuclear devices.

  1. Neutral Beam Ion Confinement in NSTX

    SciTech Connect

    D.S. Darrow; E.D. Fredrickson; S.M. Kaye; S.S. Medley; and A.L. Roquemore

    2001-07-24

    Neutral-beam (NB) heating in the National Spherical Torus Experiment (NSTX) began in September 2000 using up to 5 MW of 80 keV deuterium (D) beams. An initial assessment of beam ion confinement has been made using neutron detectors, a neutral particle analyzer (NPA), and a Faraday cup beam ion loss probe. Preliminary neutron results indicate that confinement may be roughly classical in quiescent discharges, but the probe measurements do not match a classical loss model. MHD activity, especially reconnection events (REs) causes substantial disturbance of the beam ion population.

  2. Ion beam surface modification

    NASA Technical Reports Server (NTRS)

    Dwight, D. W.

    1982-01-01

    The essential details of a study on the practical applications and mechanisms of polymer sputtering via Argon ion impact are summarized. The potential to modify the properties of polymer surfaces to improve their adherence, durability, biocompatibility, or other desirable properties by ion beam sputtering was emphasized. Ion beam milling can be of benefit as an analytical tool to obtain composition versus depth information. Ion impact from a directed ion gun source specifically etches polymer structures according to their morphologies, therefore this technique may be useful to study unknown or new morphological features. Factors addressed were related to: (1) the texture that arises on a polymer target after ion impact; (2) the chemistry of the top surface after ion impact; (3) the chemistry of sputtered films of polymeric material deposited on substrates placed adjacent to targets during ion impact; and (4) practical properties of textured polymer targets, specifically the wettability and adhesive bonding properties.

  3. 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.

  4. RHIC BEAM LOSS MONITOR SYSTEM INITIAL OPERATION.

    SciTech Connect

    WITKOVER,R.L.; MICHNOFF,R.J.; GELLER,J.M.

    1999-03-29

    The RHIC Beam Loss Monitor (BLM) System is designed to prevent beam loss quenching of the superconducting magnets, and acquire loss data. Four hundred ion chambers are located around the rings to detect losses. The required 8-decade range in signal current is compressed using an RC pre- integrator ahead of a low current amplifier. A beam abort may be triggered if fast or slow losses exceed programmable threshold levels. A micro-controller based VME module sets references and gains and reads trip status for up to 64 channels. Results obtained with the detectors in the RHIC Sextant Test and the prototype electronics in the AGS-to-RHIC (AtR) transfer line are presented along with the present status of the system.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Tomographic study of ion tracks by ion energy loss spectroscopy

    SciTech Connect

    Vacik, J.; Havranek, V.; Hnatowicz, V.; Lavrentiev, V.; Horak, P.; Fink, D.; Apel, P.

    2013-04-19

    Ion energy loss spectroscopy is suggested to determine the shape of the (latent, etched and filled) ion tracks in polymers using ion probes of various beam sizes. For a milli-probe, it can be considered as a one-dimensional tomography of many identical (rotationally symmetric) objects. For a micro-probe, the technique can be understood as a micro-tomography of the single ion track. In both cases, the ion energy loss spectroscopy requires monoenergetic ions with a low intensity (< 10{sup -3} s{sup -1}) and a well defined angular beam set-up. Here we present a study of the possible use of the ion milli-and micro-probes in a tomographic study of the ion track 3D geometry and its evolution during chemical etching.

  11. Ion beam generating apparatus

    DOEpatents

    Brown, Ian G.; Galvin, James

    1987-01-01

    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.

  12. Ion beam mixing by focused ion beam

    SciTech Connect

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

    2007-09-01

    Si amorphous (41 nm)/Cr polycrystalline (46 nm) multilayer structure was irradiated by 30 keV Ga{sup +} ions with fluences in the range of 25-820 ions/nm{sup 2} using a focused ion beam. The effect of irradiation on the concentration distribution was studied by Auger electron spectroscopy depth profiling, cross-sectional transmission electron microscopy, and atomic force microscopy. The ion irradiation did not result in roughening on the free surface. On the other hand, the Ga{sup +} irradiation produced a strongly mixed region around the first Si/Cr interface. The thickness of mixed region depends on the Ga{sup +} fluence and it is joined to the pure Cr matrix with an unusual sharp interface. With increasing fluence the width of the mixed region increases but the interface between the mixed layer and pure Cr remains sharp. TRIDYN simulation failed to reproduce this behavior. Assuming that the Ga{sup +} irradiation induces asymmetric mixing, that is during the mixing process the Cr can enter the Si layer, but the Si cannot enter the Cr layer, the experimental findings can qualitatively be explained.

  13. The AGS Booster beam loss monitor system

    SciTech Connect

    Beadle, E.R.; Bennett, G.W.; Witkover, R.L.

    1991-01-01

    A beam loss monitor system has been developed for the Brookhaven National Laboratory Booster accelerator, and is designed for use with intensities of up to 1.5 {times} 10{sup 13} protons and carbon to gold ions at 50-3 {times} 10{sup 9} ions per pulse. This system is a significant advance over the present AGS system by improving the sensitivity, dynamic range, and data acquisition. In addition to the large dynamic range achievable, it is adaptively shifted when high losses are detected. The system uses up to 80 argon filled ion chambers as detectors, as well as newly designed electronics for processing and digitizing detector outputs. The hardware simultaneously integrates each detector output, interfaces to the beam interrupt systems, and digitizes all 80 channels to 21 bits at 170 KHz. This paper discuses the design, construction, and operation of the system. 4 refs., 2 figs.

  14. Ion Beam Simulator

    Energy Science and Technology Software Center (ESTSC)

    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

  15. Ion Accelerator Merges Several Beams

    NASA Technical Reports Server (NTRS)

    Aston, G.

    1984-01-01

    Intense ion beam formed by merging multiple ion beamlets into one concentrated beam. Beamlet holes in graphite screen and focusing grids arranged in hexagonal pattern. Merged beam passes through single hole in each of aluminum accelerator and decelerator grids. Ion extraction efficiency, beam intensity, and focusing improved.

  16. 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.

  17. 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.

  18. 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.

  19. Energetic ion loss diagnostic for the Wendelstein 7-AS stellarator

    SciTech Connect

    Darrow, D. S.; Werner, A.; Weller, A.

    2001-07-01

    A diagnostic to measure the loss of energetic ions from the Wendelstein 7-AS (W7-AS) stellarator has been built. It is capable of measuring losses of both neutral beam ions and energetic ions arising from ion cyclotron resonant heating. The probe can measure losses of both clockwise and counterclockwise-going energetic ions simultaneously, and accepts a wide range of pitch angles in both directions. Initial measurements by the diagnostic are reported.

  20. Energetic Ion Loss Diagnostic for the Wendelstein 7-AS Stellarator

    SciTech Connect

    D. S. Darrow; A. Werner; A. Weller

    2000-12-07

    A diagnostic to measure the loss of energetic ions from the Wendelstein 7-AS (W7-AS) stellarator has been built. It is capable of measuring losses of both neutral beam ions and energetic ions arising from ion cyclotron resonant heating. The probe can measure losses of both clockwise and counterclockwise-going energetic ions simultaneously, and accepts a wide range of pitch angles in both directions. Initial measurements by the diagnostic are reported.

  1. RHIC beam loss monitor system design

    SciTech Connect

    Witkover, R.; Zitvogel, E.; Michnoff, R.

    1997-07-01

    The Beam Loss Monitor (BLM) System is designed to prevent the quenching of RHIC magnets due to beam loss, provide quantitative loss data, and the loss history in the event of a beam abort. The system uses 400 ion chambers of a modified Tevatron design. To satisfy fast (single turn) and slow (100 msec) loss beam criteria and provide sensitivity for studies measurements, a range of over 8 decades is needed. An RC pre-integrator reduces the dynamic range for a low current amplifier. This is digitized for data logging. The output is also applied to an analog multiplier which compensates the energy dependence, extending the range of the abort comparators. High and low pass filters separate the signal to dual comparators with independent programmable trip levels. Up to 64 channels, on 8 VME boards, are controlled by a micro-controller based VME module, decoupling it from the front-end computer (FEC) for real-time operation. Results with the detectors in the RHIC Sextant Test and the electronics in the AGS-to-RHIC (AtR) transfer line will be presented.

  2. Metal Ion Sources for Ion Beam Implantation

    SciTech Connect

    Zhao, W. J.; Zhao, Z. Q.; Ren, X. T.

    2008-11-03

    In this paper a theme touched upon the progress of metal ion sources devoted to metal ion beam implantation (MIBI) will be reviewed. A special emphasis will be given to some kinds of ion sources such as ECR, MEVVA and Cluster ion sources. A novel dual hollow cathode metal ion source named DUHOCAMIS will be introduced and discussed.

  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. 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.

  5. RHIC low energy beam loss projections

    SciTech Connect

    Satogata,T.

    2009-08-01

    ); (4) 90% collimation efficiency, with 10% of beam losses elsewhere. This is considered mildly conservative [2]; (5) Beam lifetimes range from about 1 minute (E=2.5 GeV/u) to 20 minutes (E=7-8 GeV/u); (6) The primary beam loss mechanism is space charge/IBS blowup of transverse emittance. This implies that most beam is lost at transverse apertures, particularly abort kickers and collimators. Mar 11 2008 test run data also shows some mild chronic losses around the other IR triplets. We were not using collimators during this test run. (See Fig. 1.); and (7) The RHIC ASE states that the 'maximum number of heavy ions in each ring (is) to be less than the equivalent of 2.4 x 10{sup 11} Au ions at 100 GeV/u' [3]. The total stored beam energy of this beam is 9.5 x 10{sup 15} GeV-u.

  6. Beam-beam observations in the Relativistic Heavy Ion Collider

    SciTech Connect

    Luo, Y.; Fischer, W.; White, S.

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  7. Preliminary comments about beam loss

    SciTech Connect

    Groom, D.

    1985-10-01

    A variety of beam loss questions are being investigated. They affect several design issues, ranging from machine-associated background in the detectors to the radiation lifetime of the main-ring magnets: (1) Muons. Oppositely directed muon beams from prompt muon production, primary meson decay, and a variety of other processes radiate from each IR. If they were not fanned by the insertion dipoles, the beams would be sufficiently intense and energetic that they would present a radiation hazard even after penetrating 2 km of soil or rock. (2) Machine-associated background in the IR`s. About 30 mb of the total cross section is elastic or quasi-elastic, and most of the protons are in a Gaussian spot with sigma = 9 mr. These particles are well within the machine acceptance, but there is a grey area in the tail of the distributions in which the scattered particles `almost` remain in orbit - they continue for some distance but eventually hit a wall. (3) Cryogenic load. This problem has been addressed to some degree in the RDS, but considerably more detail is needed. It appears that a very large fraction of the inelastic particle energy will be deposited here. (4) Radiation damage in the ring. The lifetime of both magnets and electronics in the tunnel might be limited by radiation due to particle loss. Early results are not reassuring. Tevatron measurements, reported to the authors by John Elias, indicate that most of the tunnel background comes from particle loss due to beam-gas collisions.

  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. 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.

  10. 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.

  11. 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.

  12. Electron Cooling of Intense Ion Beam

    SciTech Connect

    Dietrich, J.; Kamerdjiev, V.; Maier, R.; Prasuhn, D.; Stein, J.; Stockhorst, H.; Korotaev, Yu.; Meshkov, I.; Sidorin, A.; Smirnov, A.

    2006-03-20

    Results of experimental studies of the electron cooling of a proton beam at COSY (Juelich, Germany) are presented. Intensity of the proton beam is limited by two general effects: particle loss directly after the injection and development of instability in a deep cooled ion beam. Results of the instability investigations performed at COSY during last years are presented in this report in comparison with previous results from HIMAC (Chiba, Japan) CELSIUS (Uppsala, Sweden) and LEAR (CERN). Methods of the instability suppression, which allow increasing the cooled beam intensity, are described. This work is supported by RFBR grant no. 05-02-16320 and INTAS grant no. 03-54-5584.

  13. A Beam Transport and Loss simulation with electrostatic beam separator

    NASA Astrophysics Data System (ADS)

    Yang, Ming-Jen

    1997-05-01

    Eletrostatic beam separator (septa) string is used in the Fermilab fixed target program for slow extraction from Tevatron and for dividing the beam to different experimental area. The loss from beam interaction with the dividing wire plane of the septa is used to determine the alignment of individual septum within a string of many. The interpretation of the real life signal registered at the loss monitors is not always straight forward. A simulation is being done to model the beam split through septa string and the loss pattern at exisiting beam loss monitor locations. This should lead to a better understanding of the signal and help in the alignment operation.

  14. Numerical analysis of ac loss in bifilar stacks and coils of ion beam assisted deposition YBCO coated conductors

    SciTech Connect

    Nguyen, Doan N.; Ashworth, Stephen P.; Willis, Jeffrey O.

    2009-03-15

    In this paper we present a finite element model using the commercial COMSOL software package for calculating the ac loss in bifilar stacks of high temperature superconducting tape. In the model, the current-voltage relationship characterizing the superconducting properties is assumed to follow a power law. The calculations were performed for infinite bifilar stacks with different values of layer-to-layer separation D. With appropriate settings for the boundary conditions, the numerical results agree well with the analytical data obtained from a recently proposed model [J. R. Clem, Phys. Rev. B 77, 134506 (2008)]. The numerical approach was also used to investigate the end effects in a bifilar stack to answer the following question: how many layers away from the end of a stack are required before the environment of a given layer is identical to that in an infinite stack? We find that the answer to this question depends strongly on the value of D. Based on this study, a model for calculating the ac loss in bifilar noninductively wound coils with a finite number of turns is proposed.

  15. Electron beam ion source and electron beam ion trap (invited)

    SciTech Connect

    Becker, Reinard; Kester, Oliver

    2010-02-15

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not ''sorcery'' but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  16. 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.

  17. 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.

  18. H- AND PROTON BEAM LOSS COMPARISON AT SNS SUPERCONDUCTING LINAC

    SciTech Connect

    Aleksandrov, Alexander V; Galambos, John D; Plum, Michael A; Shishlo, Andrei P

    2012-01-01

    A comparison of beam loss in the superconducting part (SCL) of the Spallation Neutron Source (SNS) linac for H- and protons is presented. During the experiment the nominal beam of negative hydrogen ions in the SCL was replaced by a proton beam created by insertion of a thin stripping carbon foil placed in the low energy section of the linac. The observed significant reduction in the beam loss for protons is explained by a domination of the intra beam stripping mechanism of the beam loss for H-. The details of the experiment are discussed, and a preliminary estimation of the cross section of the reaction H- + H- -> H- + H0 + e is presented. Earlier, a short description of these studies was presented in [1].

  19. Ion beam modification of metals

    NASA Astrophysics Data System (ADS)

    Dearnaley, G.

    1990-04-01

    Energetic ions beams may be used in various ways to modify and so improve the tribological properties of metals. These methods include: — ion implantation of selected additive species; — ion beam mixing of thin deposited coatings; — ion-beam-assisted deposition of thicker overlay coatings. The first of these techniques has been widely used to modify the electronic properties of semiconductors, but has since been extended for the treatment of all classes of material. Tool steels can be strengthened by the ion implantation of nitrogen or titanium, to produce fine dispersions of hard second-phase precipitates. Solid solution strengthening, by combinations of substitutional and interstitial species, such as yttrium and nitrogen, has also been successful. Both ion beam mixing (IBM) and ion-beam-assisted deposition (IBAD) use a combination of coating and ion bombardment. In the first case, the objective is to intermix the coating and substrate by the aid of radiation-enhanced diffusion. In the latter case, the coating is densified and modified during deposition and the process can be continued in order to build up overlay coatings several μm in thickness. The surface can then be tailored, for instance to provide a hard and adherent ceramic such as silicon nitride, boron nitride or titanium nitride. It is an advantage that all the above processes can be applied at relatively low temperatures, below about 200° C, thereby avoiding distortion of precision components. Ion implantation is also being successfully applied for the reduction of corrosion, especially at high temperatures or in the atmosphere and to explore the mechanisms of oxidation. Ion-assisted coatings, being compact and adherent, provide a more substantial protection against corrosion: silicon nitride and boron nitride are potentially useful in this respect. Examples will be given of the successful application of these methods for the surface modification of metals and alloys, and developments in the

  20. 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.

  1. Study on space charge compensation in negative hydrogen ion beam

    NASA Astrophysics Data System (ADS)

    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.

  2. 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

  3. Cold atomic beam ion source for focused ion beam applications

    SciTech Connect

    Knuffman, B.; Steele, A. V.; McClelland, J. J.

    2013-07-28

    We report measurements and modeling of an ion source that is based on ionization of a laser-cooled atomic beam. We show a high brightness and a low energy spread, suitable for use in next-generation, high-resolution focused ion beam systems. Our measurements of total ion current as a function of ionization conditions support an analytical model that also predicts the cross-sectional current density and spatial distribution of ions created in the source. The model predicts a peak brightness of 2 × 10{sup 7} A m{sup −2} sr{sup −1} eV{sup −1} and an energy spread less than 0.34 eV. The model is also combined with Monte-Carlo simulations of the inter-ion Coulomb forces to show that the source can be operated at several picoamperes with a brightness above 1 × 10{sup 7} A m{sup −2} sr{sup −1} eV{sup −1}. We estimate that when combined with a conventional ion focusing column, an ion source with these properties could focus a 1 pA beam into a spot smaller than 1 nm. A total current greater than 5 nA was measured in a lower-brightness configuration of the ion source, demonstrating the possibility of a high current mode of operation.

  4. Neon Ion Beam Lithography (NIBL).

    PubMed

    Winston, Donald; Manfrinato, Vitor R; Nicaise, Samuel M; Cheong, Lin Lee; Duan, Huigao; Ferranti, David; Marshman, Jeff; McVey, Shawn; Stern, Lewis; Notte, John; Berggren, Karl K

    2011-10-12

    Existing techniques for electron- and ion-beam lithography, routinely employed for nanoscale device fabrication and mask/mold prototyping, do not simultaneously achieve efficient (low fluence) exposure and high resolution. We report lithography using neon ions with fluence <1 ion/nm(2), ∼1000× more efficient than using 30 keV electrons, and resolution down to 7 nm half-pitch. This combination of resolution and exposure efficiency is expected to impact a wide array of fields that are dependent on beam-based lithography. PMID:21899279

  5. Energy loss of coasting gold ions and deuterons in RHIC.

    SciTech Connect

    Abreu,N.; Blaskiewicz, M.; Brown, K.A.; Butler, J.J.; FischW; Harvey, M.; Tepikian, S.

    2008-06-23

    The total energy loss of coasting gold ion beams was measured at RHIC at two energies, corresponding to a gamma of 75.2 and 107.4. We describe the experiment and observations and compare the measured total energy loss with expectations from ionization losses at the residual gas, the energy loss due to impedance and synchrotron radiation. We find that the measured energy losses are below what is expected from free space synchrotron radiation. We believe that this shows evidence for suppression of synchrotron radiation which is cut off at long wavelength by the presence of the conducting beam pipe.

  6. Monte Carlo simulations of nanoscale focused neon ion beam sputtering.

    PubMed

    Timilsina, Rajendra; Rack, Philip D

    2013-12-13

    A Monte Carlo simulation is developed to model the physical sputtering of aluminum and tungsten emulating nanoscale focused helium and neon ion beam etching from the gas field ion microscope. Neon beams with different beam energies (0.5-30 keV) and a constant beam diameter (Gaussian with full-width-at-half-maximum of 1 nm) were simulated to elucidate the nanostructure evolution during the physical sputtering of nanoscale high aspect ratio features. The aspect ratio and sputter yield vary with the ion species and beam energy for a constant beam diameter and are related to the distribution of the nuclear energy loss. Neon ions have a larger sputter yield than the helium ions due to their larger mass and consequently larger nuclear energy loss relative to helium. Quantitative information such as the sputtering yields, the energy-dependent aspect ratios and resolution-limiting effects are discussed. PMID:24231648

  7. BEAM LOSS MECHANISMS IN HIGH INTENSITY LINACS

    SciTech Connect

    Plum, Michael A

    2012-01-01

    In the present operation of the Oak Ridge Spallation Neutron Source, 60-Hz, 825-us H beam pulses are accelerated to 910 MeV, and then compressed to less than a microsecond in the storage ring, to deliver 1 MW of beam power to the spallation target. The beam loss in the superconducting portion of the linac is higher than expected, and it has shown a surprising counter-intuitive correlation with quadrupole magnetic fields, with a loss minimum occurring when the quadrupoles are set to approximately half their design values. This behavior can now be explained by a recent set of experiments that show the beam loss is primarily due to intra-beam stripping. Beam halo is another important beam loss contributor, and collimation in the 2.5 MeV Medium Energy Beam Transport has proven to be an effective mitigation strategy. In this presentation, we will summarize these and other beam loss mechanisms that are important for high intensity linacs.

  8. Modeling of a multicharged ion beam line using SIMION

    NASA Astrophysics Data System (ADS)

    Korwin-Pawlowski, Michael L.; Amiz, Karima; Elsayed-Ali, Hani

    2009-06-01

    Multicharged ion beams (MCI) are promising tools to probe or modify the surface of materials with applications in microelectronics and nanotechnology. Ion beam lines are parts of the MCI systems connecting the ion source with the processing chamber and they perform the function of extracting, accelerating, decelerating, focusing and scanning the ion beam on the surface of the target. In our work we present results of modeling of an MCI beam line using the SIMION code to simulate the flight of ions, with the purpose of optimizing the yield of the line and avoiding spurious effects due to interaction of the ions with the metallic elements of the line, such as heating, outgassing and excessive Xray emission. We show that a two stage ion extractor could significantly reduce ion beam losses.

  9. Enhanced loss of fast ions during mode conversion ion Bernstein wave heating in TFTR

    SciTech Connect

    Darrow, D.S.; Majeski, R.; Fisch, N.J.; Heeter, R.F.; Herrmann, H.W.; Herrmann, M.C.; Zarnstorff, M.C.; Zweben, S.J.

    1995-12-01

    A strong interaction of fast ions with ion Bernstein waves has been observed in TFTR. It results in a large increase in the fast ion loss rate, and heats the lost particles to several MeV. The lost ions are observed at the passing/trapped boundary and appear to be either DD fusion produced tritons or accelerated D neutral beam ions. Under some conditions, enhanced loss of DT alpha particles is also seen. The losses provide experimental support for some of the elements required for alpha energy channeling.

  10. Ion beam deposited protective films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.

    1981-01-01

    Sputter deposition of adherent thin films on complex geometric surfaces by ion beam sources is examined in order to evaluate three different types of protective coatings for die materials. In the first experiment, a 30 cm diameter argon ion source was used to sputter deposit adherent metallic films up to eight microns thick on H-13 steel, and a thermal fatigue test specimen sputter deposited with metallic coatings one micron thick was immersed in liquid aluminum and cooled by water for 15,000 cycles to simulate operational environments. Results show that these materials do protect the steel by reducing thermal fatigue and thereby increasing die lifetime. The second experiment generated diamond-like carbon films using a dual beam ion source system that directed an eight cm argon ion source beam at the substrates. These films are still in the process of being evaluated for crystallinity, hardness and infrared absorption. The third experiment coated a fiber glass beam shield incorporated in the eight-cm diameter mercury ion thruster with molybdenum to ensure proper electrical and thermal properties. The coating maintained its integrity even under acceleration tests.

  11. Beam Loss Monitoring for LHC Machine Protection

    NASA Astrophysics Data System (ADS)

    Holzer, Eva Barbara; Dehning, Bernd; Effnger, Ewald; Emery, Jonathan; Grishin, Viatcheslav; Hajdu, Csaba; Jackson, Stephen; Kurfuerst, Christoph; Marsili, Aurelien; Misiowiec, Marek; Nagel, Markus; Busto, Eduardo Nebot Del; Nordt, Annika; Roderick, Chris; Sapinski, Mariusz; Zamantzas, Christos

    The energy stored in the nominal LHC beams is two times 362 MJ, 100 times the energy of the Tevatron. As little as 1 mJ/cm3 deposited energy quenches a magnet at 7 TeV and 1 J/cm3 causes magnet damage. The beam dumps are the only places to safely dispose of this beam. One of the key systems for machine protection is the beam loss monitoring (BLM) system. About 3600 ionization chambers are installed at likely or critical loss locations around the LHC ring. The losses are integrated in 12 time intervals ranging from 40 μs to 84 s and compared to threshold values defined in 32 energy ranges. A beam abort is requested when potentially dangerous losses are detected or when any of the numerous internal system validation tests fails. In addition, loss data are used for machine set-up and operational verifications. The collimation system for example uses the loss data for set-up and regular performance verification. Commissioning and operational experience of the BLM are presented: The machine protection functionality of the BLM system has been fully reliable; the LHC availability has not been compromised by false beam aborts.

  12. DATA ACQUISITION FOR SNS BEAM LOSS MONITOR SYSTEM

    SciTech Connect

    YENG,Y.GASSNER,D.HOFF,L.WITKOVER,R.

    2003-10-13

    The Spallation Neutron Source (SNS) beam loss monitor system uses VME based electronics to measure the radiation produced by lost beam. Beam loss signals from cylindrical argon-filled ion chambers and neutron detectors will be conditioned in analog front-end (AFE) circuitry. These signals will be digitized and further processed in a dedicated VME crate. Fast beam inhibit and low-level, long-term loss warnings will be generated to provide machine protection. The fast loss data will have a bandwidth of 35kHz. While the low level, long-term loss data will have much higher sensitivity. This is further complicated by the 3 decade range of intensity as the Ring accumulates beam. Therefore a bandwidth of 100kHz and dynamic range larger than 21 bits data acquisition system will be required for this purpose. Based on the evaluation of several commercial ADC modules in preliminary design phase, a 24 bits Sigma-Delta data acquisition VME bus card was chosen as the SNS BLM digitizer. An associated vxworks driver and EPICS device support module also have been developed at BNL. Simulating test results showed this system is fully qualified for both fast loss and low-level, long-term loss application. The first prototype including data acquisition hardware setup and EPICS software (running database and OPI clients) will be used in SNS Drift Tube Linac (DTL) system commissioning.

  13. Maskless, resistless ion beam lithography

    SciTech Connect

    Ji, Qing

    2003-03-10

    As the dimensions of semiconductor devices are scaled down, in order to achieve higher levels of integration, optical lithography will no longer be sufficient for the needs of the semiconductor industry. Alternative next-generation lithography (NGL) approaches, such as extreme ultra-violet (EUV), X-ray, electron-beam, and ion projection lithography face some challenging issues with complicated mask technology and low throughput. Among the four major alternative NGL approaches, ion beam lithography is the only one that can provide both maskless and resistless patterning. As such, it can potentially make nano-fabrication much simpler. This thesis investigates a focused ion beam system for maskless, resistless patterning that can be made practical for high-volume production. In order to achieve maskless, resistless patterning, the ion source must be able to produce a variety of ion species. The compact FIB system being developed uses a multicusp plasma ion source, which can generate ion beams of various elements, such as O{sub 2}{sup +}, BF{sub 2}{sup +}, P{sup +} etc., for surface modification and doping applications. With optimized source condition, around 85% of BF{sub 2}{sup +}, over 90% of O{sub 2}{sup +} and P{sup +} have been achieved. The brightness of the multicusp-plasma ion source is a key issue for its application to maskless ion beam lithography. It can be substantially improved by optimizing the source configuration and extractor geometry. Measured brightness of 2 keV He{sup +} beam is as high as 440 A/cm{sup 2} {center_dot} Sr, which represents a 30x improvement over prior work. Direct patterning of Si thin film using a focused O{sub 2}{sup +} ion beam has been investigated. A thin surface oxide film can be selectively formed using 3 keV O{sub 2}{sup +} ions with the dose of 10{sup 15} cm{sup -2}. The oxide can then serve as a hard mask for patterning of the Si film. The process flow and the experimental results for directly patterned poly-Si features

  14. Using neutral beams as a light ion beam probe (invited)

    SciTech Connect

    Chen, Xi; Heidbrink, W. W.; Van Zeeland, M. A.; Pace, D. C.; Petty, C. C.; Fisher, R. K.; Kramer, G. J.; Nazikian, R.; Austin, M. E.; Hanson, J. M.; Zeng, L.

    2014-11-15

    By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fields appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.

  15. Beam Loss Studies for Rare Isotope Driver Linacs Final Report

    SciTech Connect

    Wangler, T P; Kurennoy, S S; Billen, J H; Crandall, K R; Qiang, J; Ryne, R D; Mustapha, B; Ostroumov, P; Zhao, Q; York, and R. C.

    2008-03-26

    The Fortran 90 RIAPMTQ/IMPACT code package is a pair of linked beam-dynamics simulation codes that have been developed for end-to-end computer simulations of multiple-charge-state heavy-ion linacs for future exotic-beam facilities. These codes have multiple charge-state capability, and include space-charge forces. The simulations can extend from the low-energy beam-transport line after an ECR ion source to the end of the linac. The work has been performed by a collaboration including LANL, LBNL, ANL, and MSU. The code RIAPMTQ simulates the linac front-end beam dynamics including the LEBT, RFQ, and MEBT. The code IMPACT simulates the beam dynamics of the main superconducting linac. The codes have been benchmarked for rms beam properties against previously existing codes at ANL and MSU. The codes allow high-statistics runs on parallel supercomputing platforms, particularly at NERSC at LBNL, for studies of beam losses. The codes also run on desktop PC computers for low-statistics work. The code package is described in more detail in a recent publication [1] in the Proceedings of PAC07 (2007 US Particle Accelerator Conference). In this report we describe the main activities for the FY07 beam-loss studies project using this code package.

  16. 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

  17. Ion-beam-driven electrostatic ion cyclotron instabilities

    SciTech Connect

    Miura, A.; Okuda, H.; Ashour-Abdalla, M.

    1982-10-01

    We present results of numerical simulations on the electrostatic ion cyclotron instabilities driven by the ion beam parallel to the magnetic field. For the beam speed exceeding the thermal speed of background ions and the beam temperature much lower than the background ion temperature, it is found that the instability results in strong perpendicular heating and slowing down of parallel drift of the beam ions, leading to the saturation of the instability. Applications to plasma heating and space plasma physics are discussed.

  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. PMID:26513553

  19. Energetic ion losses caused by magnetohydrodynamic activity resonant and non-resonant with energetic ions in Large Helical Device

    NASA Astrophysics Data System (ADS)

    Ogawa, Kunihiro; Isobe, Mitsutaka; Toi, Kazuo; Shimizu, Akihiro; Spong, Donald A.; Osakabe, Masaki; Yamamoto, Satoshi; the LHD Experiment Group

    2014-09-01

    Experiments to reveal energetic ion dynamics associated with magnetohydrodynamic activity are ongoing in the Large Helical Device (LHD). Interactions between beam-driven toroidal Alfvén eigenmodes (TAEs) and energetic ions have been investigated. Energetic ion losses induced by beam-driven burst TAEs have been observed using a scintillator-based lost fast-ion probe (SLIP) in neutral beam-heated high β plasmas. The loss flux of co-going beam ions increases as the TAE amplitude increases. In addition to this, the expulsion of beam ions associated with edge-localized modes (ELMs) has been also recognized in LHD. The SLIP has indicated that beam ions having co-going and barely co-going orbits are affected by ELMs. The relation between ELM amplitude and ELM-induced loss has a dispersed structure. To understand the energetic ion loss process, a numerical simulation based on an orbit-following model, DELTA5D, that incorporates magnetic fluctuations is performed. The calculation result shows that energetic ions confined in the interior region are lost due to TAE instability, with a diffusive process characterizing their loss. For the ELM, energetic ions existing near the confinement/loss boundary are lost through a convective process. We found that the ELM-induced loss flux measured by SLIP changes with the ELM phase. This relation between the ELM amplitude and measured ELM-induced loss results in a more dispersed loss structure.

  20. Negative ion based neutral beam injector for JT-60U

    NASA Astrophysics Data System (ADS)

    Okumura, Y.; Araki, M.; Hanada, M.; Inoue, T.; Kunieda, S.; Kuriyama, M.; Matsuoka, M.; Mizuno, M.; Ohara, Y.; Tanaka, M.; Watanabe, K.

    1992-10-01

    A 500 keV, 10 MW neutral beam injector is to be constructed in JT-60 Upgrade for the experiments of current drive and heating of heat density core plasmas. This is the first neutral beam injector in the world using negative ions as the primary ions. In the design, D- ion beams of 44 A, 500 keV are produced by two ion sources (22 A/each ion source) and neutralized in a long gas neutralizer. The total system efficiency is about 40%. The ion source is a cesium-seeded multicusp volume source having a three stage electrostatic accelerator. To reduce the stripping loss of D- ions in the accelerator, the ion source should be operated at a low pressure of 0.3 Pa with a current density of 13 mA/cm2. The first test of the full-size negative ion source is scheduled from middle of 1993.

  1. Integration of scanning probes and ion beams

    SciTech Connect

    Persaud, A.; Park, S.J.; Liddle, J.A.; Schenkel, T.; Bokor, J.; Rangelow, I.

    2005-03-30

    We report the integration of a scanning force microscope with ion beams. The scanning probe images surface structures non-invasively and aligns the ion beam to regions of interest. The ion beam is transported through a hole in the scanning probe tip. Piezoresistive force sensors allow placement of micromachined cantilevers close to the ion beam lens. Scanning probe imaging and alignment is demonstrated in a vacuum chamber coupled to the ion beam line. Dot arrays are formed by ion implantation in resist layers on silicon samples with dot diameters limited by the hole size in the probe tips of a few hundred nm.

  2. Ion loss processes in the stratosphere

    NASA Technical Reports Server (NTRS)

    Prasad, B. S. N.; Chandramma, S.

    1985-01-01

    Small ions consisting of aggregates of a few molecules determine th stratospheric electrical parameters such as conductivity, mobility, etc. The small ion density is controlled by the ionizing mechanisms for the production of ions and electrons and the loss processes for these charged particles. Ion production in stratosphere is chiefly due to galactic cosmic rays, and the loss processes due to recombination and attachment. Free electrons do not exist at stratospheric heights. The primary positive ion O2+ and the electrons are converted into complex clusters of positive and negative ions. The equilibrium ion density is governed by the equation of continuity for the production and loss of these ions. In the generalized equation of continuity, the gain or loss of ions due to transport is neglected. When aerosols or particulates are not present in the atmosphere, ions are loss due to ion-ion recombination. In the presence of aerosols, small ions can also be lost by attachment to the aerosols, and thus aerosols are likely to cause perturbations in the stratosphere electrification. A simplified model approach is adopted to study the effect of aerosols on the equilibrium ion density. The results of the analysis for the equatorial station Thumba (8.5 deg N) are presented.

  3. 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.

  4. Spallation neutron source beam loss monitor system

    NASA Astrophysics Data System (ADS)

    Gassner, D.; Witkover, R.; Cameron, P.; Power, J.

    2000-11-01

    The Spallation Neutron Source facility to be built at ORNL is designed to accumulate 2×1014 protons at 1.0 GeV and deliver them to the experimental target in one bunch at 60 Hz. To achieve this goal and protect the machine from excessive radiation activation, an uncontrolled loss criteria of 1 part in 104 (1 W/m) has been specified. Measured losses will be conditioned to provide machine tuning data, a beam abort trigger, and logging of loss history. The design of the distributed loss monitor system utilizing argon-filled glass ionization chambers and scintillator-photomultipliers will be presented.

  5. 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.

  6. 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.)

  7. Measuring Fast Ion Losses in a Reversed Field Pinch Plasma

    NASA Astrophysics Data System (ADS)

    Bonofiglo, P. J.; Anderson, J. K.; Almagri, A. F.; Kim, J.; Clark, J.; Capecchi, W.; Sears, S. H.

    2015-11-01

    The reversed field pinch (RFP) provides a unique environment to study fast ion confinement and transport. The RFP's weak toroidal field, strong magnetic shear, and ability to enter a 3D state provide a wide range of dynamics to study fast ions. Core-localized, 25 keV fast ions are sourced into MST by a tangentially injected hydrogen/deuterium neutral beam. Neutral particle analysis and measured fusion neutron flux indicate enhanced fast ion transport in the plasma core. Past experiments point to a dynamic loss of fast ions associated with the RFP's transition to a 3D state and with beam-driven, bursting magnetic modes. Consequently, fast ion transport and losses in the RFP have garnered recent attention. Valuable information on fast-ion loss, such as energy and pitch distributions, are sought to provide a better understanding of the transport mechanisms at hand. We have constructed and implemented two fast ion loss detectors (FILDs) for use on MST. The FILDs have two, independent, design concepts: collecting particles as a function of v⊥ or with pitch greater than 0.8. In this work, we present our preliminary findings and results from our FILDs on MST. This research is supported by US DOE.

  8. 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.

  9. Obliquely incident ion beam figuring

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Dai, Yifan; Xie, Xuhui; Li, Shengyi

    2015-10-01

    A new ion beam figuring (IBF) technique, obliquely incident IBF (OI-IBF), is proposed. In OI-IBF, the ion beam bombards the optical surface obliquely with an invariable incident angle instead of perpendicularly as in the normal IBF. Due to the higher removal rate in oblique incidence, the process time in OI-IBF can be significantly shortened. The removal rates at different incident angles were first tested, and then a test mirror was processed by OI-IBF. Comparison shows that in the OI-IBF technique with a 30 deg incident angle, the process time was reduced by 56.8%, while keeping the same figure correcting ability. The experimental results indicate that the OI-IBF technique is feasible and effective to improve the surface correction process efficiency.

  10. 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.

  11. 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.

  12. 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.

  13. The ATLAS Beam Condition and Beam Loss Monitors

    NASA Astrophysics Data System (ADS)

    Dolenc, I.

    2010-04-01

    The primary goal of ATLAS Beam Condition Monitor (BCM) and Beam Loss Monitor (BLM) is to protect the ATLAS Inner Detector against damaging LHC beam incidents by initiating beam abort in case of beam failures. Poly-crystalline Chemical Vapour Deposition (pCVD) diamond was chosen as the sensor material for both systems. ATLAS BCM will provide real-time monitoring of instantaneous particle rates close to the interaction point (IP) of ATLAS spectrometer. Using fast front-end and signal processing electronics the time-of-flight and pulse amplitude measurements will be performed to distinguish between normal collisions and background events due to natural or accidental beam losses. Additionally, BCM will also provide coarse relative luminosity information. A second system, the ATLAS BLM, is an independent system which was recently added to complement the BCM. It is a current measuring system and was partially adopted from the BLM system developed by the LHC beam instrumentation group with pCVD diamond pad sensors replacing the ionisation chambers. The design of both systems and results of operation in ATLAS framework during the commissioning with cosmic rays will be reported in this contribution.

  14. Benchmarking of collimation tracking using RHIC beam loss data.

    SciTech Connect

    Robert-Demolaize,G.; Drees, A.

    2008-06-23

    State-of-the-art tracking tools were recently developed at CERN to study the cleaning efficiency of the Large Hadron Collider (LHC) collimation system. In order to estimate the prediction accuracy of these tools, benchmarking studies can be performed using actual beam loss measurements from a machine that already uses a similar multistage collimation system. This paper reviews the main results from benchmarking studies performed with specific data collected from operations at the Relativistic Heavy Ion Collider (RHIC).

  15. 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

  16. RHIC Beam Loss Monitor System Design and Test

    NASA Astrophysics Data System (ADS)

    Witkover, R.; Zitvogel, E.; Michnoff, R.

    1997-05-01

    The Beam Loss Monitor System is designed to prevent the quenching of RHIC magnets due to beam loss, provide quantitative loss data, and the loss history in the event of a beam abort. To satisfy fast (single turn) and slow (100 msec) loss beam abort criteria and provide sensitivity for studies measurements, a range of over 8 decades is needed. The system uses 400 ion chambers of a modified Tevatron design. An RC pre-integrator reduces the dynamic range for a low current amplifier. This is digitized by a standard RHIC VME MADC preceded by a switchable gain amplifier. The output also goes to an analog multiplier used to reduce energy dependence, extending the range of the abort comparators. Fast and slow filters separate the signal to dual comparators with independent trip levels. The gains, fast and slow abort levels, and abort bit masks are set for each channel on receipt of specific RHIC Event Codes. Up to 64 channels, on 8 VME boards, are controlled by a BNL designed micro-controller based VME module, decoupling it from the front-end computer for real-time operation.

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

    DOEpatents

    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.

  18. EDITORIAL: Negative ion based neutral beam injection

    NASA Astrophysics Data System (ADS)

    Hemsworth, R. S.

    2006-06-01

    It is widely recognized that neutral beam injection (NBI), i.e. the injection of high energy, high power, beams of H or D atoms, is a flexible and reliable system that has been the main heating system on a large variety of fusion devices, and NBI has been chosen as one of the three heating schemes of the International Tokomak Reactor (ITER). To date, all the NBI systems but two have been based on the neutralization (in a simple gas target) of positive hydrogen or deuterium ions accelerated to <100 keV/nucleon. Above that energy the neutralization of positive ions falls to unacceptably low values, and higher energy neutral beams have to be created by the neutralization of accelerated negative ions (in a simple gas target), as this remains high (approx60%) up to >1 MeV/nucleon. Unfortunately H- and D- are difficult to create, and the very characteristic that makes them attractive, the ease with which the electron is detached from the ion, means that it is difficult to create high concentrations or fluxes of them, and it is difficult to avoid substantial, collisional, losses in the extraction and acceleration processes. However, there has been impressive progress in negative ion sources and accelerators over the past decade, as demonstrated by the two pioneering, operational, multi-megawatt, negative ion based, NBI systems at LHD (180 keV, H0) and JT-60U (500 keV, D0), both in Japan. Nevertheless, the system proposed for ITER represents a substantial technological challenge as an increase is required in beam energy, to 1 MeV, D0, accelerated ion (D-) current, to 40 A, accelerated current density, 200 A m-2 of D-, and pulse length, to 1 h. At the Fourth IAEA Technical Meeting on Negative Ion Based Neutral Beam Injectors, hosted by the Consorzio RFX, Padova, Italy, 9-11 May 2005, the status of the R&D aimed at the realization of the injectors for ITER was presented. Because of the importance of this development to the success of the ITER project, participants at that

  19. Focused electron and ion beam systems

    DOEpatents

    Leung, Ka-Ngo; Reijonen, Jani; Persaud, Arun; Ji, Qing; Jiang, Ximan

    2004-07-27

    An electron beam system is based on a plasma generator in a plasma ion source with an accelerator column. The electrons are extracted from a plasma cathode in a plasma ion source, e.g. a multicusp plasma ion source. The beam can be scanned in both the x and y directions, and the system can be operated with multiple beamlets. A compact focused ion or electron beam system has a plasma ion source and an all-electrostatic beam acceleration and focusing column. The ion source is a small chamber with the plasma produced by radio-frequency (RF) induction discharge. The RF antenna is wound outside the chamber and connected to an RF supply. Ions or electrons can be extracted from the source. A multi-beam system has several sources of different species and an electron beam source.

  20. 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.

  1. The electromagnetic ion cyclotron beam anisotropy instability

    NASA Technical Reports Server (NTRS)

    Peter Gary, S.; Schriver, David

    1987-01-01

    Electromagnetic instabilities driven by an anisotropic, relatively cool ion beam are studied for the case in which both the beam and the instabilities propagate parallel or antiparallel to a uniform magnetic field. At modest beam-core relative drift speeds, sufficiently large perpendicular-to-parallel beam temperature ratios and sufficiently large plasma beta, the mode of fastest growth rate is the ion cyclotron beam anisotropy instability. Because the right-hand polarized waves observed upstream of slow shocks in the earth's magnetotail can lead to the appropriate beam anisotropy, the ion cyclotron instability may be present and account for the left-hand polarized magnetic waves observed there. Also, because of its relatively low phase speed, the ion cyclotron beam anisotropy instability may provide the scattering necessary for ion Fermi acceleration at slow shocks of sufficiently high plasma beta.

  2. Negative Ion Beam Extraction and Emittance

    SciTech Connect

    Holmes, Andrew J. T.

    2007-08-10

    The use of magnetic fields to both aid the production of negative ions and suppress the co-extracted electrons causes the emittance and hence the divergence of the negative ion beam to increase significantly due to the plasma non-uniformity from jxB drift. This drift distorts the beam-plasma meniscus and experimental results of the beam emittance are presented, which show that non-uniformity causes the square of the emittance to be proportional to the 2/3 power of the extracted current density. This can cause the divergence of the negative ion beam to be significantly larger than its positive ion counterpart. By comparing results from positive and negative ion beam emittances from the same source, it is also possible to draw conclusions about their vulnerability to magnetic effects. Finally emittances of caesiated and un-caesiated negative ion beams are compared to show how the surface and volume modes of production interact.

  3. Loss of atomic oxygen in mass spectrometer ion sources.

    NASA Technical Reports Server (NTRS)

    Lake, L. R.; Nier, A. O.

    1973-01-01

    A gas beam consisting of a mixture of atomic and molecular oxygen has been directed at the ion source of a mass spectrometer like those used in sounding rockets for determining the neutral composition of the lower thermosphere. The loss of atomic oxygen on mass spectrometer surfaces was evaluated by flagging the beam in several ways and comparing the experimental results with predicted values. The results obtained suggest that in rocket flights using similar instruments the atomic oxygen densities computed assuming no-loss conditions may be low by a factor of 2.5. Studies made using a beam containing tracer O-18 indicate that carbon dioxide observed when atomic oxygen enters the source is formed in a reaction involving atomic oxygen from the beam and carbon monoxide from the surfaces bombarded.

  4. Beam Ion Driven Instabilities in NSTX

    SciTech Connect

    N.N. Gorelenkov; E. Belova; H.L. Berk; C.Z. Cheng; E. Fredrickson; W. Heidbrink; S. Kaye; G. Kramer

    2003-11-07

    A low-field, low-aspect-ratio device such as NSTX (National Spherical Torus Experiment) is an excellent testbed to study the ITER-relevant physics of fast-particle confinement that is of major importance for burning plasmas. The low Alfvin speed in NSTX offers a window to the super-Alfvinic regime expected in ITER. Effects such as the large FLR, orbit width, strong shaping, and high thermal and fast-ion betas make this effort a greater challenge. We report on the linear stability of different Alfvin eigenmode (AE) branches and compare theory with experimental data. Low-frequency MHD activities, {approx}100 kHz, on NSTX are often observed and identified as the toroidicity-induced AEs (TAE) driven by beam ions. Sometimes they are accompanied by beam ion losses in H-mode, high q(0) plasmas. Numerical analysis using the NOVA-K code shows good agreement with the experimental data. The TAE instability was compared in experiments on NSTX and DIII-D. With very similar plasma conditions, we tested the theoretical prediction that the toroidal mode number of the most unstable TAEs scales with the machine minor radius, n {approx} a. In NSTX, TAEs are observed with n = 1-2, whereas in DIII-D n = 4-7. The confirmation of n scaling validates the predictive capabilities of theoretical tools (NOVA-K) for studying ITER plasmas. In the high-frequency range, recent observations of rich sub-ion cyclotron frequency MHD activities in NSTX suggest that new instabilities are excited, which we identify as Global shear AEs (GAEs). Similar to the compressional AEs (CAEs), GAEs are destabilized by the Doppler-shifted cyclotron resonance in the presence of 80 keV neutral-beam injection. To simulate GAE/CAEs in realistic NSTX plasma conditions, we have developed a nonlinear hybrid kinetic-MHD code, HYM, which is capable of computing the mode structure, saturation, and energetic particle transport.

  5. Molecular Ion Beam Transportation for Low Energy Ion Implantation

    SciTech Connect

    Kulevoy, T. V.; Kropachev, G. N.; Seleznev, D. N.; Yakushin, P. E.; Kuibeda, R. P.; Kozlov, A. V.; Koshelev, V. A.; Hershcovitch, A.; Johnson, B. M.; Gushenets, V. I.; Oks, E. M.; Polozov, S. M.; Poole, H. J.

    2011-01-07

    A joint research and development of steady state intense boron ion sources for 100's of electron-volt ion implanters has been in progress for the past five years. Current density limitation associated with extracting and transporting low energy ion beams result in lower beam currents that in turn adversely affects the process throughput. The transport channel with electrostatic lenses for decaborane (B{sub 10}H{sub 14}) and carborane (C{sub 2}B{sub 10}H{sub 12}) ion beams transportation was developed and investigated. The significant increase of ion beam intensity at the beam transport channel output is demonstrated. The transport channel simulation, construction and experimental results of ion beam transportation are presented.

  6. Plasma formed ion beam projection lithography system

    SciTech Connect

    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.

  7. 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.

  8. 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.

  9. The Electron Beam Ion Source (EBIS)

    ScienceCinema

    Brookhaven Lab

    2010-01-08

    Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen

  10. The Electron Beam Ion Source (EBIS)

    SciTech Connect

    Brookhaven Lab

    2009-06-09

    Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen

  11. 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.

  12. Treatment Planning for Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Greilich, Steffen; Jäkel, Oliver

    2010-01-01

    Beams of charged particles offer an improved dose conformation to the target volume as compared to photon radiotherapy, with better sparing of normal tissue structures close to the target. In addition, beams of ions heavier than helium exhibit a strong increase of the Linear Energy Transfer (LET) in the Bragg peak as compared to the entrance region, resulting in a higher biological efficiency in the target region. These physical and biological properties make ion beams more favorable for radiation therapy of cancer than photon beams. As a consequence, particle therapy with heavy ions has gained increasing interest worldwide. To fully benefit from the advantages of ion radiotherapy, appropriate treatment planning has to be done—taking into account the specific characteristics of ion beams, e.g. the inverted depth-dose profile, nuclear fragmentation, and increase radiobiological effectiveness. This paper describes in brief the approach taken at GSI Darmstadt and HIT Heidelberg for an active 3D beam scanning system.

  13. Fast ion JET diagnostics: confinement and losses

    SciTech Connect

    Kiptily, V. G.; Pinches, S. D.; Sharapov, S. E.; Syme, D. B.; Cecconello, M.; Darrow, D.; Hill, K.; Goloborod'ko, V.; Yavorskij, V.; Johnson, T.; Murari, A.; Reich, M.; Gorini, G.; Zoita, V.

    2008-03-12

    A study of magnetically confined fast ions in tokamaks plays an important role in burning plasma research. To reach ignition and steady burning of a reactor plasma an adequate confinement of energetic ions produced by NBI heating, accelerated with ICRF and born in fusion reactions is essential to provide efficient heating of the bulk plasma. Thus, investigation of the fast ion behaviour is an immediate task for present-day large machines, such as JET, in order to understand the main mechanisms of slowing down, redistribution and losses, and to develop optimal plasma scenarios. Today's JET has an enhanced suite of fast ion diagnostics both of confined and lost ions that enable to significantly contribute to this important area of research. Fast ion populations of p, d, t, {sup 3}He and {sup 4}He, made with ICRF, NBI, and fusion reactions have been investigated in experiments on JET with sophisticated diagnostics in conventional and shear-reversed plasmas, exploring a wide range of effects. This paper will introduce to the JET fast-ion diagnostic techniques and will give an overview of recent observations. A synergy of the unique diagnostic set was utilised in JET, and studies of the response of fast ions to MHD modes (e.g. tornado modes, sawtooth crashes), fast {sup 3}He-ions behaviour in shear-reversed plasmas are impressive examples of that. Some results on fast ion losses in JET experiments with various levels of the toroidal field ripple will be demonstrated.

  14. Charged fusion product and fast ion loss in TFTR

    SciTech Connect

    Zweben, S.J.; Darrow, D.S.; Fredrickson, E.D.; Mynick, H.E.; White, R.B.; Biglari, H.; Bretz, N.; Budny, R.; Bush, C.E.; Chang, C.S.; Chen, L.; Cheng, C.Z.; Fu, G.Y.; Hammett, G.W.; Hawryluk, R.J.; Hosea, J.; Johnson, L.; Mansfield, D.; McGuire, K.; Medley, S.S.; Nazikian, R.; Owens, D.K.; Park, H.; Park, J.; Phillips, C.K.; Schivell, J.; Stratton, B.C.; Ulrickson, M.; Wilson, R.; Young, K.M.; Boivin, R.; Machuzak, J.S.; Woskov, P.; Fisher, R.; McChesney, J.; Fonck, R.; McKee, G.; Tuszewski, M.

    1993-03-01

    Several different fusion product and fast ion loss processes have been observed in TFTR using an array of pitch angle, energy and time resolved scintillator detectors located near the vessel wall. For D-D fusion products (3 MeV protons and 1 MeV tritons) the observed loss is generally consistent with expected first-orbit loss for Ip < 1.4 MA, except near the outer midplane where stochastic TF ripple loss dominates when Ip > I MA. However, at higher currents, Ip = 1.4--2.5 MA, an NM induced D-D fusion product loss can be up to 3-4 times larger than the first-orbit loss, particularly at high beam powers, P {ge} 25 MW. The MHD induced loss of 100 KeV neutron beam ions and {approximately}0.5 MeV ICRF minority tail tons has also been measured {le} 459 below the outer midplane. be potential implications of these results for D-T alpha particle experiments in TFTR and ITER are described.

  15. Charged fusion product and fast ion loss in TFTR

    SciTech Connect

    Zweben, S.J.; Darrow, D.S.; Fredrickson, E.D.; Mynick, H.E.; White, R.B.; Biglari, H.; Bretz, N.; Budny, R.; Bush, C.E.; Chang, C.S.; Chen, L.; Cheng, C.Z.; Fu, G.Y.; Hammett, G.W.; Hawryluk, R.J.; Hosea, J.; Johnson, L.; Mansfield, D.; McGuire, K.; Medley, S.S.; Nazikian, R.; Owens, D.K.; Park, H.; Park, J.; Phillips, C.K.; Schivell, J.; Stratton, B.C.; Ulrickson, M.; Wilson, R.; Young, K.M. (Princeton Univ., NJ (United Sta

    1993-03-01

    Several different fusion product and fast ion loss processes have been observed in TFTR using an array of pitch angle, energy and time resolved scintillator detectors located near the vessel wall. For D-D fusion products (3 MeV protons and 1 MeV tritons) the observed loss is generally consistent with expected first-orbit loss for Ip < 1.4 MA, except near the outer midplane where stochastic TF ripple loss dominates when Ip > I MA. However, at higher currents, Ip = 1.4--2.5 MA, an NM induced D-D fusion product loss can be up to 3-4 times larger than the first-orbit loss, particularly at high beam powers, P [ge] 25 MW. The MHD induced loss of 100 KeV neutron beam ions and [approximately]0.5 MeV ICRF minority tail tons has also been measured [le] 459 below the outer midplane. be potential implications of these results for D-T alpha particle experiments in TFTR and ITER are described.

  16. Simulating Electron Cloud Effects in Heavy-Ion Beams

    SciTech Connect

    Cohen, R.H.; Friedman, A.; Lund, S.W.; Molvik, A.W.; Azevedo, T.; Vay, J.-L.; Stoltz, P.; Veitzer, S.

    2004-08-04

    Stray electrons can be introduced in heavy ion fusion accelerators 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 summarize here results from several studies of electron-cloud accumulation and effects: (1) Calculation of the electron cloud produced by electron desorption from computed beam ion loss; the importance of ion scattering is shown; (2) Simulation of the effect of specified electron cloud distributions on ion beam dynamics. We find electron cloud variations that are resonant with the breathing mode of the beam have the biggest impact on the beam (larger than other resonant and random variations), and that the ion beam is surprisingly robust, with an electron density several percent of the beam density required to produce significant beam degradation in a 200-quadrupole system. We identify a possible instability associated with desorption and resonance with the breathing mode. (3) Preliminary investigations of a long-timestep algorithm for electron dynamics in arbitrary magnetic fields.

  17. Laser cooling of a stored ion beam: A first step towards crystalline beams

    SciTech Connect

    Hangst, J.S.

    1992-09-01

    This report discusses: a brief introduction to storage rings; crystalline beams; laser cooling of ion beams; description of astrid-the experimental setup; first experiments with lithium 7 ion beam; experiments with erbium 166 ion beams; further experiments with lithium 7 ion beams; beam dynamics, laser cooling,and crystalline beams in astrid; possibilities for further study in astrid.

  18. Ion optics of RHIC electron beam ion source

    SciTech Connect

    Pikin, A.; Alessi, J.; Beebe, E.; Kponou, A.; Okamura, M.; Raparia, D.; Ritter, J.; Tan, Y.; Kuznetsov, G.

    2012-02-15

    RHIC electron beam ion source has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.

  19. TOPICAL REVIEW Dosimetry for ion beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Karger, Christian P.; Jäkel, Oliver; Palmans, Hugo; Kanai, Tatsuaki

    2010-11-01

    Recently, ion beam radiotherapy (including protons as well as heavier ions) gained considerable interest. Although ion beam radiotherapy requires dose prescription in terms of iso-effective dose (referring to an iso-effective photon dose), absorbed dose is still required as an operative quantity to control beam delivery, to characterize the beam dosimetrically and to verify dose delivery. This paper reviews current methods and standards to determine absorbed dose to water in ion beam radiotherapy, including (i) the detectors used to measure absorbed dose, (ii) dosimetry under reference conditions and (iii) dosimetry under non-reference conditions. Due to the LET dependence of the response of films and solid-state detectors, dosimetric measurements are mostly based on ion chambers. While a primary standard for ion beam radiotherapy still remains to be established, ion chamber dosimetry under reference conditions is based on similar protocols as for photons and electrons although the involved uncertainty is larger than for photon beams. For non-reference conditions, dose measurements in tissue-equivalent materials may also be necessary. Regarding the atomic numbers of the composites of tissue-equivalent phantoms, special requirements have to be fulfilled for ion beams. Methods for calibrating the beam monitor depend on whether passive or active beam delivery techniques are used. QA measurements are comparable to conventional radiotherapy; however, dose verification is usually single field rather than treatment plan based. Dose verification for active beam delivery techniques requires the use of multi-channel dosimetry systems to check the compliance of measured and calculated dose for a representative sample of measurement points. Although methods for ion beam dosimetry have been established, there is still room for developments. This includes improvement of the dosimetric accuracy as well as development of more efficient measurement techniques.

  20. 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.

  1. Optical Faraday Cup for Heavy Ion Beams

    SciTech Connect

    Bieniosek, Frank; Bieniosek, F.M.; Eylon, S.; Roy, P.K.; Yu, S.S.

    2007-06-25

    We have been using alumina scintillators for imaging beams in heavy-ion beam fusion experiments in 2 to 4 transverse dimensions [1]. The scintillator has a limited lifetime under bombardment by the heavy ion beams. As a possible replacement for the scintillator, we are studying the technique of imaging the beam on a gas cloud. A gas cloud for imaging the beam may be created on a solid hole plate placed in the path of the beam, or by a localized gas jet. It is possible to image the beam using certain fast-quenching optical lines that closely follow beam current density and are independent of gas density. We describe this technique and show preliminary experimental data. This approach has promise to be a new fast beam current diagnostic on a nanosecond time scale.

  2. 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.

  3. Focused Ion Beam Technology for Optoelectronic Devices

    NASA Astrophysics Data System (ADS)

    Reithmaier, J. P.; Bach, L.; Forchel, A.

    2003-08-01

    High-resolution proximity free lithography was developed using InP as anorganic resist for ion beam exposure. InP is very sensitive on ion beam irradiation and show a highly nonlinear dose dependence with a contrast function comparable to organic electron beam resists. In combination with implantation induced quantum well intermixing this new lithographic technique based on focused ion beams is used to realize high performance nano patterned optoelectronic devices like complex coupled distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers.

  4. 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.

  5. 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.

  6. Fast ion loss diagnostic plans for the National Spherical Torus Experiment

    SciTech Connect

    Darrow, D. S.; Bell, R.; Johnson, D. W.; Kugel, H.; Wilson, J. R.; Cecil, F. E.; Maingi, R.; Krasilnikov, A.; Alekseyev, A.

    2001-01-01

    The prompt loss of neutral beam ions from the National Spherical Torus Experiment is expected to be between 12% and 42% of the total 5 MW of beam power. There may, in addition, be losses of fast ions arising from high harmonic fast wave (HHFW) heating. Most of the lost ions will strike the HHFW antenna or the neutral beam dump. To measure these losses in the 2000 experimental campaign, thermocouples in the antenna, several infrared camera views, and a Faraday cup lost ion probe will be employed. The probe will measure loss of fast ions with E>1 keV at three radial locations, giving the scrape-off length of the fast ions.

  7. Analysis of beam loss induced abort kicker instability

    SciTech Connect

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

    2012-05-20

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

  8. BEAM LOSS MITIGATION IN THE OAK RIDGE SPALLATION NEUTRON SOURCE

    SciTech Connect

    Plum, Michael A

    2012-01-01

    The Oak Ridge Spallation Neutron Source (SNS) accelerator complex routinely delivers 1 MW of beam power to the spallation target. Due to this high beam power, understanding and minimizing the beam loss is an ongoing focus area of the accelerator physics program. In some areas of the accelerator facility the equipment parameters corresponding to the minimum loss are very different from the design parameters. In this presentation we will summarize the SNS beam loss measurements, the methods used to minimize the beam loss, and compare the design vs. the loss-minimized equipment parameters.

  9. 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.

  10. PRELIMINARY DESIGN OF THE BEAM LOSS MONITORING SYSTEM FOR THE SNS.

    SciTech Connect

    WITKOVER,R.; GASSNER,D.

    2002-05-06

    The SNS to be built at Oak Ridge National Laboratory will provide a high average intensity 1 GeV beam to produce spallation neutrons. Loss of a even small percentage of this intense beam would result in high radiation. The Beam Loss Monitor (ELM) system must detect such small, long term losses yet be capable of measuring infrequent short high losses. The large dynamic range presents special problems for the system design. Ion chambers will be used as the detectors. A detector originally designed for the FNAL Tevatron, was considered but concerns about ion collection times and low collection efficiency at high loss rates favor a new design. The requirements and design concepts of the proposed approach will be presented. Discussion of the design and testing of the ion chambers and the analog j-Point end electronics will be presented. The overall system design will be described.

  11. 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.

  12. RFQ Designs and Beam-Loss Distributions for IFMIF

    SciTech Connect

    Jameson, Robert A

    2007-01-01

    The IFMIF 125 mA cw 40 MeV accelerators will set an intensity record. Minimization of particle loss along the accelerator is a top-level requirement and requires sophisticated design intimately relating the accelerated beam and the accelerator structure. Such design technique, based on the space-charge physics of linear accelerators (linacs), is used in this report in the development of conceptual designs for the Radio-Frequency-Quadrupole (RFQ) section of the IFMIF accelerators. Design comparisons are given for the IFMIF CDR Equipartitioned RFQ, a CDR Alternative RFQ, and new IFMIF Post-CDR Equipartitioned RFQ designs. Design strategies are illustrated for combining several desirable characteristics, prioritized as minimum beam loss at energies above ~ 1 MeV, low rf power, low peak field, short length, high percentage of accelerated particles. The CDR design has ~0.073% losses above 1 MeV, requires ~1.1 MW rf structure power, has KP factor 1.7,is 12.3 m long, and accelerates ~89.6% of the input beam. A new Post-CDR design has ~0.077% losses above 1 MeV, requires ~1.1 MW rf structure power, has KP factor 1.7 and ~8 m length, and accelerates ~97% of the input beam. A complete background for the designs is given, and comparisons are made. Beam-loss distributions are used as input for nuclear physics simulations of radioactivity effects in the IFMIF accelerator hall, to give information for shielding, radiation safety and maintenance design. Beam-loss distributions resulting from a ~1M particle input distribution representative of the IFMIF ECR ion source are presented. The simulations reported were performed with a consistent family of codes. Relevant comparison with other codes has not been possible as their source code is not available. Certain differences have been noted but are not consistent over a broad range of designs and parameter range. The exact transmission found by any of these codes should be treated as indicative, as each has various sensitivities in

  13. Luminosity Loss due to Beam Distortion and the Beam-Beam Instability

    SciTech Connect

    Wu, Juhao; Raubenheimer, T.O.; Chao, A.W.; Seryi, A.; Sramek, C.K.; /Rice U.

    2005-06-30

    In a linear collider, sources of emittance dilution such as transverse wakefields or dispersive errors will couple the vertical phase space to the longitudinal position within the beam (the so-called ''banana effect''). When the Intersection Point (IP) disruption parameter is large, these beam distortions will be amplified by a single bunch kink instability which will lead to luminosity loss. We study this phenomena both analytically using linear theory and via numerical simulation. In particular, we examine the dependence of the luminosity loss on the wavelength of the beam distortions and the disruption parameter. This analysis may prove useful when optimizing the vertical disruption parameter for luminosity operation with given beam distortions.

  14. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, Joshua (Inventor); Hubbell, Theodore E. (Inventor)

    1987-01-01

    A surface of a steel substrate is nitrided without external heating by exposing it to a beam of nitrogen ions under low pressure, a pressure much lower than that employed for ion-nitriding. An ion source is used instead of a glow discharge. Both of these features reduce the introduction of impurities into the substrate surface.

  15. Measurement and analysis of internal loss and injection efficiency for continuous-wave blue semipolar ( 20 2 ¯ 1 ¯ ) III-nitride laser diodes with chemically assisted ion beam etched facets

    NASA Astrophysics Data System (ADS)

    Becerra, Daniel L.; Kuritzky, Leah Y.; Nedy, Joseph; Saud Abbas, Arwa; Pourhashemi, Arash; Farrell, Robert M.; Cohen, Daniel A.; DenBaars, Steven P.; Speck, James S.; Nakamura, Shuji

    2016-02-01

    Continuous-wave blue semipolar ( 20 2 ¯ 1 ¯ ) III-nitride laser diodes were fabricated with highly vertical, smooth, and uniform mirror facets produced by chemically assisted ion beam etching. Uniform mirror facets are a requirement for accurate experimental determination of internal laser parameters, including internal loss and injection efficiency, which were determined to be 9 cm-1 and 73%, respectively, using the cavity length dependent method. The cavity length of the uncoated devices was varied from 900 μm to 1800 μm, with threshold current densities ranging from 3 kA/cm2 to 9 kA/cm2 and threshold voltages ranging from 5.5 V to 7 V. The experimentally determined internal loss was found to be in good agreement with a calculated value of 9.5 cm-1 using a 1D mode solver. The loss in each layer was calculated and in light of the analysis several modifications to the laser design are proposed.

  16. Masking Technique for Ion-Beam Sputter Etching

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    Improved process for fabrication of integrated circuits developed. Technique utilizes simultaneous ion-beam sputter etching and carbon sputter deposition in conjunction with carbon sputter mask or organic mask decomposed to produce carbon-rich sputter-mask surface. Sputter etching process replenishes sputter mask with carbon to prevent premature mask loss.

  17. Enhancements to the Compact Helical System fast ion loss probe

    SciTech Connect

    Darrow, D.S.; Isobe, M.; Kondo, T.; Sasao, M.; the CHS Group

    1999-01-01

    A scintillator-based fast ion loss probe has been used to measure 40 keV neutral beam ion loss from Compact Helical System plasmas. Modifications have recently been made to the probe to expand the range of gyroradius covered and to increase the probe acceptance at low pitch angles. In addition, a lamp has been installed inside the probe to facilitate calibration of the scintillator position within the field of view of the video camera. Finally, a Faraday cup structure, integral with the scintillator, has been added to allow direct measurement of the ion current to the probe. This last feature allows much easier absolute calibration of the diagnostic. {copyright} {ital 1999 American Institute of Physics.}

  18. Precise measurements of the energy losses of heavy ions

    SciTech Connect

    Bichsel, H.; Hiraoka, T. |

    1995-12-31

    Accurate measurements of the energy loss of all charged particles are needed to determine the reliability of the Bethe theory of stopping power. Few measurements have been made for particles with energies greater than 20 MeV/u. A first step to accurate measurements is to establish the precision of an experimental method. The authors report here about the recent energy loss measurements for 290 MeV/u carbon ions from the HIMAC. They have been made with the method used for 70 MeV protons. The ion beam traverses an absorber of thickness t and the residual range of the ions is measured with a water container of adjustable thickness (``range gauge``).

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

    SciTech Connect

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

    2013-04-19

    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 Registered-Sign 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 {approx}10%.

  20. 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.

  1. Laser ion source for low charge heavy ion beams

    SciTech Connect

    Okamura,M.; Pikin, A.; Zajic, V.; Kanesue, T.; Tamura, J.

    2008-08-03

    For heavy ion inertial fusion application, a combination of a laser ion source and direct plasma injection scheme into an RFQ is proposed. The combination might provide more than 100 mA of singly charged heavy ion beam from a single laser shot. A planned feasibility test with moderate current is also discussed.

  2. Modified betatron for ion beam fusion

    SciTech Connect

    Rostoker, N.; Fisher, A.

    1986-01-01

    An intense neutralized ion beam can be injected and trapped in magnetic mirror or tokamak geometry. The details of the process involve beam polarization so that the beam crosses the fringing fields without deflection and draining the polarization when the beam reaches the plasma. Equilibrium requires that a large betatron field be added in tokamak geometry. In mirror geometry a toroidal field must be added by means of a current along the mirror axis. In either case, the geometry becomes that of the modified betatron which has been studied experimentally and theoretically in recent years. We consider beams of d and t ions with a mean energy of 500 kev and a temperature of about 50 kev. The plasma may be a proton plasma with cold ions. It is only necessary for beam trapping or to carry currents. The ion energy for slowing down is initially 500 kev and thermonuclear reactions depend only on the beam temperature of 50 kev which changes very slowly. This new configuration for magnetic confinement fusion leads to an energy gain of 10--20 for d-t reactions whereas previous studies of beam target interaction predicted a maximum energy gain of 3--4. The high beam energy available with pulsed ion diode technology is also essential for advanced fuels. 16 refs., 3 figs.

  3. Formation of multi-charged ion beams by focusing effect of mid-electrode on electron cyclotron resonance ion source

    SciTech Connect

    Imai, Youta Kimura, Daiju; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-15

    We are constructing a tandem type electron cyclotron resonance ion source (ECRIS) and a beam line for extracting ion beams. The ion beam is extracted from the second stage by an accel-decel extraction system with a single-hole and the ion beam current on each electrode is measured. The total ion beam current is measured by a faraday cup downstream the extraction electrodes. We measure these currents as a function of the mid-electrode potential. We also change the gap length between electrodes and perform similar measurement. The behaviors of these currents obtained experimentally against the mid-electrode potential show qualitatively good agreement with a simple theoretical consideration including sheath potential effects. The effect of mid-electrode potential is very useful for decreasing the beam loss for enhancing ion beam current extracted from ECRIS.

  4. 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.

  5. Beam imaging diagnostics for heavy ion beam fusion experiments

    SciTech Connect

    Bieniosek, F.M.; Prost, L.; Ghiorso, W.

    2003-05-01

    We are developing techniques for imaging beams in heavy-ion beam fusion experiments in the HIF-VNL in 2 to 4 transverse dimensions. The beams in current experiments range in energy from 50 keV to 2 MeV, with beam current densities from <10 to 200 mA/cm{sup 2}, and pulse lengths of 4 to 20 {micro}s. The beam energy will range up to 10 MeV in near-future beam experiments. The imaging techniques, based on kapton films and optical scintillators, complement and, in some cases, may replace mechanical slit scanners. The kapton film images represent a time-integrated image on the film exposed to the beam. The optical scintillator utilizes glass and ceramic scintillator material imaged by a fast, image-intensified CCD-based camera. We will discuss the techniques, results, and plans for implementation of the diagnostics on the beam experiments.

  6. A Distributed Radiator, Heavy Ion Target with Realistic Ion Beams

    NASA Astrophysics Data System (ADS)

    Callahan, Debra A.; Tabak, Max

    1997-11-01

    Recent efforts in heavy ion target design have centered around the distributed radiator design of Tabak(M. Tabak, Bull. Am. Phys. Soc., Vol 41, No 7, 1996.). The initial distributed radiator target assumed beams with a uniform radial density distribution aimed directly along the z axis. Chamber propagation simulations indicate that the beam distribution is more nearly Gaussian at best focus. In addition, more than two beams will be necessary to carry the required current; this means that the beams must be angled to allow space for the final focusing systems upstream. We will describe our modifications to the distributed radiator target to allow realistic beams and realistic beam angles.

  7. 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.

  8. 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.

  9. 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

  10. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    NASA Astrophysics Data System (ADS)

    Sartori, E.; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Sonato, P.; Veltri, P.

    2014-02-01

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  11. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    SciTech Connect

    Sartori, E. Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P.; Sonato, P.

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  12. Surface modification using MeV ion beams

    NASA Technical Reports Server (NTRS)

    Tombrello, T. A.

    1983-01-01

    Electronic excitation induced by MeV/amu ion beams in a variety of materials has been employed successfully for a number of applications. The examples that will be presented are: modification of the surface reflectivities of optical materials; sputter-erosion of dielectrics; and enhancement of the adhesion of thin film coatings. All of these effects arise from the loss of energy by the ion beam to electrons in the target material; the mechanisms involved are at best qualitatively understood. This paper will stress not only the exploitation of such high energy bombardment techniques but will also briefly review attempts to expose the underlying causes.

  13. 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.

  14. 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.

  15. 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.

  16. Ion manipulation device to prevent loss of ions

    DOEpatents

    Tolmachev, Aleksey; Smith, Richard D; Ibrahim, Yehia M; Anderson, Gordon A; Baker, Erin M

    2015-03-03

    An ion manipulation method and device to prevent loss of ions is disclosed. The device includes a pair of surfaces. An inner array of electrodes is coupled to the surfaces. A RF voltage and a DC voltage are alternately applied to the inner array of electrodes. The applied RF voltage is alternately positive and negative so that immediately adjacent or nearest neighbor RF applied electrodes are supplied with RF signals that are approximately 180 degrees out of phase.

  17. Novel method for unambiguous ion identification in mixed ion beams extracted from an electron beam ion trap

    SciTech Connect

    Meissl, W.; Simon, M. C.; Crespo Lopez-Urrutia, J. R.; Tawara, H.; Ullrich, J.; Winter, HP.; Aumayr, F.

    2006-09-15

    A novel technique to identify small fluxes of mixed highly charged ion beams extracted from an electron beam ion trap is presented and practically demonstrated. The method exploits projectile charge state dependent potential emission of electrons as induced by ion impact on a metal surface to separate ions with identical or very similar mass-to-charge ratio.

  18. ION BEAM ETCHING EFFECTS IN BIOLOGICAL MICROANALYSIS

    EPA Science Inventory

    Oxygen ion beam sputter etching used in SIMS has been shown to produce morphologic effects which have similarities and differences in comparison to rf plasma etching of biological specimens. Sputter yield variations resulting from structural microheterogeneity are illustrated (e....

  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. Ion Beam Scattering by Background Helium

    NASA Astrophysics Data System (ADS)

    Grillet, Anne; Hughes, Thomas; Boerner, Jeremiah

    2015-11-01

    The presence of background gases can cause charged particle beams to become more diffuse due to scattering. Calculations for the transport of an ion beam have been performed using Aleph, a particle-in-cell plasma modeling code, and verified against a general envelop equation for charged particle beams. We have investigated the influence of background helium on the coherence and transmitted current of the ion beam. Collisions between ions and neutral particles were calculated assuming isotropic elastic scattering. Since this tends to predict larger scattering angles than are expected at high energies, these are conservative estimates for beam scattering. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration.

  1. Low energy ion loss at Mars

    NASA Astrophysics Data System (ADS)

    Curry, S.; Liemohn, M.; Fang, X.; Ma, Y.

    2012-04-01

    Current data observations and modeling efforts have indicated that the low-energy pick-up ions on Mars significantly contribute to the overall escape rate. Due to the lack of a dipole magnetic field, the solar wind directly interacts with the dayside upper atmosphere causing particles to be stripped away. In this study, we use a 3-D Monte Carlo test particle simulation with virtual detectors to observe low energy ions (< 50 eV) in the Mars space environment. We will present velocity space distributions that can capture the asymmetric and non-gyrotropic features of particle motion. The effect of different solar conditions will also be discussed with respect to ion fluxes at various spatial locations as well as overall loss in order to robustly describe the physical processes controlling the distribution of planetary ions and atmospheric escape.

  2. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, J.

    1985-01-01

    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.

  3. Beam dynamics in heavy ion induction LINACS

    SciTech Connect

    Smith, L.

    1981-10-01

    Interest in the use of an induction linac to accelerate heavy ions for the purpose of providing the energy required to initiate an inertially confined fusion reaction has stimulated a theoretical effort to investigate various beam dynamical effects associated with high intensity heavy ion beams. This paper presents a summary of the work that has been done so far; transverse, longitudinal and coupled longitudinal transverse effects are discussed.

  4. 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)

  5. 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.

  6. Superintense ion beam with high energy density

    NASA Astrophysics Data System (ADS)

    Dudnikov, Vadim; Dudnikova, Galina

    2008-04-01

    The energy density of ion beam accumulated in a storage ring can be increased dramatically with using of space charge compensation as was demonstrated in experiments [1]. The intensity of said superintense beam can be far greater than a space charge limit without space charge compensation. The model of secondary plasma build up with secondary ion-electron emission as a source of delayed electrons has been presented and discussed. This model can be used for explanation of bunched beam instability with electron surviving after gap, for prediction of e-cloud generation in coasting and long bunches beam, and can be important for pressure rise in worm and cold sections of storage rings. A fast desorption by ion of physically adsorbed molecules can explain a ``first pulse Instability''. Application of this model for e-p instability selfstabilization and superintense circulating beam accumulation is considered. Importance of secondary plasma for high perveance ion beam stabilization in ion implantation will be considered. Preliminary results of simulation of electron and ion accumulation will be presented. [1]. Belchenko et al., Xth International Particle Accelerator Conference, Protvino, 1977, Vol. 2, p. 287.

  7. Suppressing Loss of Ions in an Atomic Clock

    NASA Technical Reports Server (NTRS)

    Prestage, John; Chung, Sang

    2010-01-01

    An improvement has been made in the design of a compact, highly stable mercury- ion clock to suppress a loss of ions as they are transferred between the quadrupole and higher multipole ion traps. Such clocks are being developed for use aboard spacecraft for navigation and planetary radio science. The modification is also applicable to ion clocks operating on Earth: indeed, the success of the modification has been demonstrated in construction and operation of a terrestrial breadboard prototype of the compact, highly stable mercury-ion clock. Selected aspects of the breadboard prototype at different stages of development were described in previous NASA Tech Briefs articles. The following background information is reviewed from previous articles: In this clock as in some prior ion clocks, mercury ions are shuttled between two ion traps, one a 16- pole linear radio-frequency trap, while the other is a quadrupole radio-frequency trap. In the quadrupole trap, ions are tightly confined and optical state selection from a 202Hg lamp is carried out. In the 16-pole trap, the ions are more loosely confined and atomic transitions are interrogated by use of a microwave beam at approximately 40.507 GHz. The trapping of ions effectively eliminates the frequency pulling that would otherwise be caused by collisions between clock atoms and the wall of a gas cell. The shuttling of the ions between the two traps enables separation of the state-selection process from the clock microwave-resonance process, so that each of these processes can be optimized independently of the other. This is similar to the operation of an atomic beam clock, except that with ions the beam can be halted and reversed as ions are shuttled back and forth between the two traps. When the two traps are driven at the same radio frequency, the strength of confinement can be reduced near the junction between the two traps, depending upon the relative phase of the RF voltage used to operate each of the two traps, and

  8. Energy loss of ions implanted in MOS dielectric films

    NASA Astrophysics Data System (ADS)

    Shyam, Radhey

    Energy loss measurements of ions in the low kinetic energy regime have been made on as-grown SiO2(170-190nm) targets. Singly charged Na + ions with kinetic energies of 2-5 keV and highly charged ions Ar +Q (Q=4, 8 and 11) with a kinetic energy of 1 keV were used. Excitations produced by the ion energy loss in the oxides were captured by encapsulating the irradiated oxide under a top metallic contact. The resulting Metal-Oxide-Semiconductor (MOS) devices were probed with Capacitance-Voltage (C V) measurements and extracted the flatband voltages from the C-V curves. The C-V results for singly charged ion experiments reveal that the changes in the flatband voltage and slope for implanted devices relative to the pristine devices can be used to delineate effects due to implanted ions only and ion induced damage. The data shows that the flatband voltage shifts and C-V slope changes are energy dependent. The observed changes in flatband voltage which are greater than those predicted by calculations scaled for the ion dose and implantation range (SRIM). These results, however, are consistent with a columnar recombination model, where electron-hole pairs are created due to the energy deposited by the implanted ions within the oxide. The remaining holes left after recombination losses are diffused through the oxide at the room temperature and remain present as trapped charges. Comparison of the data with the total number of the holes generated gives a fractional yield of 0.0124 which is of the same order as prior published high energy irradiation experiments. Additionally, the interface trap density, extracted from high and low frequency C-V measurements is observed to increase by one order of magnitude over our incident beam energy. These results confirm that dose- and kinetic energy -dependent effects can be recorded for singly charged ion irradiation on oxides using this method. Highly charged ion results also confirm that dose as well as and charge-dependent effects can

  9. Sweating. Fluid and ion losses and replacement.

    PubMed

    McCutcheon, L J; Geor, R J

    1998-04-01

    In the horse, sweat is produced by apocrine glands which are present over most haired and nonhaired skin. Although sweat secretion is initiated under a number of circumstances, the central drive for sweating in response to a thermal stimulus is the primary mechanism for its production. Sweating is an essential and primary mechanism for heat dissipation during exercise or exposure to hot ambient conditions. The rate of sweat production will reflect the interaction of numerous factors, including exercise intensity, ambient conditions, state of hydration, and the training or heat acclimation status of the individual horse. Thus, the sweating rates produced in response to an exercise-induced thermal load can be further increased by high ambient temperature or humidity which reduces evaporative efficiency, thereby contributing to the rate of rise in core body temperature. Equine sweat is an isotonic to slightly hypertonic secretion with sodium, chloride, and potassium contributing the major ionic components. The ionic composition of equine sweat is largely rate dependent and therefore is affected by factors such as ambient conditions and exercise intensity which result in elevations in sodium concentration in response to increases in sweating rate. Large sweat fluid losses associated with prolonged exercise will incur significant ion deficits, leading to alterations in skeletal muscle ion content and the potential for muscular dysfunction. With respect to exercise performance, however, the more important consequence of sweat fluid losses is the impairment of temperature regulation that accompanies severe dehydration. Although it is advantageous to restore a proportion of the fluid and ion losses incurred during prolonged exercise, few strategies will fully and safely replace the electrolyte losses incurred. Nevertheless, daily electrolyte supplementation of a good-quality diet will provide an effective method of replacing sweat ion losses during training and competition

  10. Fermilab main injector: High intensity operation and beam loss control

    NASA Astrophysics Data System (ADS)

    Brown, Bruce C.; Adamson, Philip; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K.; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-07-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at 400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  11. Analysis of beam loss mechanism in the Project X linac

    SciTech Connect

    Carneiro, J.-P.; Lebedev, V.; Nagaitsev, S.; Ostiguy, J.-F.; Solyak, N.; /Fermilab

    2011-03-01

    Minimization of the beam losses in a multi-MW H{sup -} linac such as ProjectX to a level below 1 W/m is a challenging task. The impact of different mechanism of beam stripping, including stripping in electric and magnetic fields, residual gas, blackbody radiation and intra-beam stripping, is analyzed. Other sources of beam losses are misalignements of beamline elements and errors in RF fields and phases. We present in this paper requirements for dynamic errors and correction schemes to keep beam losses under control.

  12. A pencil beam algorithm for helium ion beam therapy

    SciTech Connect

    Fuchs, Hermann; Stroebele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar

    2012-11-15

    Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the

  13. A synchronous beam sweeper for heavy ions

    SciTech Connect

    Bogaty, J.M.

    1989-01-01

    The Argonne Tandem Linac Accelerator System (ATLAS) facility at Argonne National Laboratory provides a wide range of accelerated heavy ions from the periodic table. Frequently, the beam delivery rate of 12 MHz is too fast for the type of experiment on line. Reaction by-products from a target bombardment may have a decay interval much longer than the dead time between beam bunches. To prevent data from being corrupted by incoming ions a beam sweeper was developed which synchronously eliminates selected beam bunches to suit experimental needs. As the SWEEPER is broad band (DC to 6 MHz) beam delivery rates can be instantaneously changed. Ion beam bunches are selectively kicked out by an electrostatic dipole electrode pulsed to 2 kVDC. The system has been used for almost three years with several hundred hours of operating time logged to date. Beam bunch delivery rates of 6 MHz down to 25 kHz have been provided. Since this is a non-resonant system any beam delivery rate from 6 MHz down to zero can be set. In addition, burst modes have been used where beam is supplied in 12 MHz bursts and then shut down for a period of time set by the user. 3 figs.

  14. Thermoacoustic imaging using heavy ion beams

    SciTech Connect

    Claytor, T.N.; Tesmer, J.R.; Deemer, B.C.; Murphy, J.C.

    1995-10-01

    Ion beams have been used for surface modification, semiconductor device fabrication and for material analysis, which makes ion-material interactions of significant importance. Ion implantation will produce new compositions near the surface by ion mixing or directly by implanting desired ions. Ions exchange their energy to the host material as they travel into the material by several different processes. High energy ions ionize the host atoms before atomic collisions transfer the remaining momentum and stop the incident ion. As they penetrate the surface, the low energy ions ionize the host atoms, but also have a significantly large momentum transfer mechanism near the surface of the material. This leads to atoms, groups of atoms and electrons being ejected from the surface, which is the momentum transfer process of sputtering. This talk addresses the acoustic waves generated during ion implantation using modulated heavy ion beams. The mechanisms for elastic wave generation during ion implantation, in the regimes where sputtering is significant and where implantation is dominant and sputtering is negligible, has been studied. The role of momentum transfer and thermal energy production during ion implantation was compared to laser generated elastic waves in an opaque solid as a reference, since laser generated ultrasound has been extensively studied and is fairly well understood. The thermoelastic response dominated in both high and low ion energy regimes since, apparently, more energy is lost to thermal heat producing mechanisms than momentum transfer processes. The signal magnitude was found to vary almost linearly with incident energy as in the laser thermoelastic regime. The time delays for longitudinal and shear waves-were characteristic of those expected for a purely thermal heating source. The ion beams are intrinsically less sensitive to the albedo of the surface.

  15. Beam current controller for laser ion source

    SciTech Connect

    Okamura, Masahiro

    2014-10-28

    The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

  16. Graphene engineering by neon ion beams

    DOE PAGESBeta

    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

  17. Characterizing and Controlling Beam Losses at the LANSCE Facility

    SciTech Connect

    Rybarcyk, Lawrence J.

    2012-09-12

    The Los Alamos Neutron Science Center (LANSCE) currently provides 100-MeV H{sup +} and 800-MeV H{sup -} beams to several user facilities that have distinct beam requirements, e.g. intensity, micropulse pattern, duty factor, etc. Minimizing beam loss is critical to achieving good performance and reliable operation, but can be challenging in the context of simultaneous multi-beam delivery. This presentation will discuss various aspects related to the observation, characterization and minimization of beam loss associated with normal production beam operations in the linac.

  18. 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.

  19. 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.

  20. Ion-beam depth-profiling studies of leached glasses

    SciTech Connect

    Houser, C.A.; Tsong, I.S.T.; White, W.B.; Wintenberg, A.L.; Miller, P.D.; Moak, C.D.

    1981-01-01

    Ion-beam depth-profiling was carried out on three different glasses leached (or hydrated) in deionized water using /sup 1/H(/sup 19/F,..cap alpha gamma..)/sup 16/O nuclear reaction, secondary ion mass spectrometry (SIMS) and sputter-induced photon spectrometry (SIPS) techniques. The depth-profiles show an interdiffusion mechanism in which the sodium ions in the glass are depleted and replaced by hydrogen (H/sup +/) or hydronium (H/sub 3/O/sup +/) ions from the solution. The leaching behavior does not show significant difference whether the glass surface is fractured or polished. Problems of mobile ion migration caused by ion bombardment and loss of hydrogen during analysis are discussed.

  1. 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.

  2. Ion sources and targets for radioactive beams

    SciTech Connect

    Schiffer, J.P.; Back, B.B.; Ahmad, I.

    1995-08-01

    A high-intensity ISOL-type radioactive beam facility depends critically on the performance of the target/ion source system. We developed a concept for producing high-intensity secondary beams of fission fragments, such as {sup 132}Sn, using a two-part target and ion source combination. The idea involves stopping a 1000-kW beam of 200-MeV deuterons in a target of Be or U to produce a secondary beam of neutrons. Just behind the neutron production target is a second target, typically a porous form of UC, coupled to an ISOL-type ion source. In December 1994, we tested this concept with 200-MeV deuterons at low intensity in an experiment at the NSCL. The yields of characteristic gamma rays were measured and confirmed our predictions.

  3. Precise formation of geometrically focused ion beams

    SciTech Connect

    Davydenko, V.I.; Ivanov, A.A.; Korepanov, S.A.; Kotelnikov, I.A.

    2006-03-15

    Geometrically focused intense neutral beams for plasma diagnostic consist of many elementary beams formed by a multiaperture ion-optical system and aimed at the focal point. In real conditions, some of the elementary beams may have increased angular divergence and/or deviate from the intended direction, thus diminishing the neutral beam density at the focus. Several improvements to the geometrical focusing are considered in the article including flattening of the plasma profile across the emission surface, using of quasi-Pierce electrodes at the beam periphery, and minimizing the deviation of the electrodes from the spherical form. Application of these measures to the neutral beam Russian diagnostic injector developed in Budker Institute of Nuclear Physics allows an increase of neutral beam current density in the focus by {approx}50%.

  4. Simulation of loss of uranium ions due to charge changing processes in the CSRm ring

    NASA Astrophysics Data System (ADS)

    Zheng, Wen-Heng; Yang, Jian-Cheng; Li, Peng; Li, Zhong-Shan; Shang, Peng; Qu, Guo-Feng; Ge, Wen-Wen; Tang, Mei-Tang; Sha, Xiao-Ping

    2015-04-01

    Significant beam loss caused by the charge exchange processes and ion impact-induced outgassing may restrict the maximum number of accelerated heavy ions during the high intensity operation of an accelerator. In order to control beam loss due to charge exchange processes and confine the generated desorption gas, tracking of the beam loss distribution and installation of absorber blocks with low-desorption rate material at appropriate locations in the main Cooler Storage Ring (CSRm) at the Institute of Modern Physics, Lanzhou, will be performed. The loss simulation of uranium ions with electron-loss is presented in this report and the conclusion is that most charge changed particles are lost in the second dipole of the super-period structure. The calculation of the collimation efficiency of the CSRm ring will be continued in the future. Supported by National Natural Science Foundation of China (11305227)

  5. Ion beams from laser-generated plasmas

    NASA Technical Reports Server (NTRS)

    Hughes, R. H.; Anderson, R. J.; Gray, L. G.; Rosenfeld, J. P.; Manka, C. K.; Carruth, M. R.

    1980-01-01

    The paper describes the space-charge-limited beams produced by the plasma blowoffs generated by 20-MW bursts of 1.06-micron radiation from an active Q-switched Nd:YAG laser. Laser power densities near 10 to the 11th/sq cm on solid targets generate thermalized plasma plumes which drift to a 15-kV gridded extraction gap where the ions are extracted, accelerated, and electrostatically focused; the spatially defined ion beams are then magnetically analyzed to determine the charge state content in the beams formed from carbon, aluminum, copper, and lead targets. This technique preserves time-of-flight (TOF) information in the plasma drift region, which permits plasma ion temperatures and mass flow velocities to be determined from the Maxwellian ion curve TOF shapes for the individual charge species.

  6. Ion beam driven warm dense matter experiments

    NASA Astrophysics Data System (ADS)

    Bieniosek, F. M.; Ni, P. A.; Leitner, M.; Roy, P. K.; More, R.; Barnard, J. J.; Kireeff Covo, M.; Molvik, A. W.; Yoneda, H.

    2007-11-01

    We report plans and experimental results in ion beam-driven warm dense matter (WDM) experiments. Initial experiments at LBNL are at 0.3-1 MeV K+ beam (below the Bragg peak), increasing toward the Bragg peak in future versions of the accelerator. The WDM conditions are envisioned to be achieved by combined longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. Initial experiments include an experiment to study transient darkening at LBNL; and a porous target experiment at GSI heated by intense heavy-ion beams from the SIS 18 storage ring. Further experiments will explore target temperature and other properties such as electrical conductivity to investigate phase transitions and the critical point.

  7. 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.

  8. 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.

  9. Measurements of Prompt and MHD-Induced Fast Ion Loss from National Spherical Torus Experiment Plasmas

    SciTech Connect

    D.S. Darrow; S.S. Medley; A.L. Roquemore; W.W. Heidbrink; A. Alekseyev; F.E. Cecil; J. Egedal; V.Ya. Goloborod'ko; N.N. Gorelenkov; M. Isobe; S. Kaye; M. Miah; F. Paoletti; M.H. Redi; S.N. Reznik; A. Rosenberg; R. White; D. Wyatt; V.A. Yavorskij

    2002-10-15

    A range of effects may make fast ion confinement in spherical tokamaks worse than in conventional aspect ratio tokamaks. Data from neutron detectors, a neutral particle analyzer, and a fast ion loss diagnostic on the National Spherical Torus Experiment (NSTX) indicate that neutral beam ion confinement is consistent with classical expectations in quiescent plasmas, within the {approx}25% errors of measurement. However, fast ion confinement in NSTX is frequently affected by magnetohydrodynamic (MHD) activity, and the effect of MHD can be quite strong.

  10. 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.

  11. Proposed LLNL electron beam ion trap

    SciTech Connect

    Marrs, R.E.; Egan, P.O.; Proctor, I.; Levine, M.A.; Hansen, L.; Kajiyama, Y.; Wolgast, R.

    1985-07-02

    The interaction of energetic electrons with highly charged ions is of great importance to several research fields such as astrophysics, laser fusion and magnetic fusion. In spite of this importance there are almost no measurements of electron interaction cross sections for ions more than a few times ionized. To address this problem an electron beam ion trap (EBIT) is being developed at LLNL. The device is essentially an EBIS except that it is not intended as a source of extracted ions. Instead the (variable energy) electron beam interacting with the confined ions will be used to obtain measurements of ionization cross sections, dielectronic recombination cross sections, radiative recombination cross sections, energy levels and oscillator strengths. Charge-exchange recombinaion cross sections with neutral gasses could also be measured. The goal is to produce and study elements in many different charge states up to He-like xenon and Ne-like uranium. 5 refs., 2 figs.

  12. Medical applications of ion beam processes

    NASA Astrophysics Data System (ADS)

    Sioshansi, P.

    The use of ions beams for treatment of surfaces in medical prostheses has gained increasing interest in the past few years. The application of ion beams has taken different forms: (1) ion implantation has been used for increasing the hardness and wear resistance of the new generation titanium based alloys, as well as reducing the wear of the mating polyethylene component used in orthopedic total joint replacement. Spire Corporation has been successful in commercializing ion implantation technology and is processing several thousand artificial knees and hips per year. (Spire uses the tradename IONGUARD™ for this application.) (2) Similarly, ion implantation has proven to be very effective for increasing the corrosion resistance of the Co-Cr based alloys that have traditionally been used in orthopedic prostheses. This application should be of particular interest in resolving the issues surrounding ion release problems associated with these alloys. (3) Ion beam etching/milling has been used for producing a highly textured surface for tissue ingrowth in applications ranging from porous orthopedic implants and percutaneous devices to artificial skin and the process should have a significant impact in this application. (4) There are indications that ion implantation is a useful process for increasing biocompatibility and tissue attachment on metallic samples. This subject deserves considerable attention in the coming years.

  13. 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.

  14. 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.

  15. Cavity loss factors for non-ultrarelativistic beams

    SciTech Connect

    Kurennoy, S.S.

    1998-12-31

    Cavity loss factors can be easily computed for ultrarelativistic beams using time-domain codes like MAFIA or ABCI. However, for non-ultrarelativistic beams the problem is more complicated because of difficulties with its numerical formulation in the time domain. The authors calculate the loss factors of a non-relativistic bunch and compare results with the relativistic case.

  16. 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.

  17. Scintillator-based diagnostic for fast ion loss measurements on DIII-D.

    PubMed

    Fisher, R K; Pace, D C; García-Muñoz, M; Heidbrink, W W; Muscatello, C M; Van Zeeland, M A; Zhu, Y B

    2010-10-01

    A new scintillator-based fast ion loss detector has been installed on DIII-D with the time response (>100 kHz) needed to study energetic ion losses induced by Alfvén eigenmodes and other MHD instabilities. Based on the design used on ASDEX Upgrade, the diagnostic measures the pitch angle and gyroradius of ion losses based on the position of the ions striking the two-dimensional scintillator. For fast time response measurements, a beam splitter and fiberoptics couple a portion of the scintillator light to a photomultiplier. Reverse orbit following techniques trace the lost ions to their possible origin within the plasma. Initial DIII-D results showing prompt losses and energetic ion loss due to MHD instabilities are discussed. PMID:21033833

  18. Upgrade of the electron beam ion trap in Shanghai

    NASA Astrophysics Data System (ADS)

    Lu, D.; Yang, Y.; Xiao, J.; Shen, Y.; Fu, Y.; Wei, B.; Yao, K.; Hutton, R.; Zou, Y.

    2014-09-01

    Over the last few years the Shanghai electron beam ion trap (EBIT) has been successfully redesigned and rebuilt. The original machine, developed under collaboration with the Shanghai Institute of Applied Physics, first produced an electron beam in 2005. It could be tuned with electron energies between 1 and 130 keV and beam current up to 160 mA. After several years of operation, it was found that several modifications for improvements were necessary to reach the goals of better electron optics, higher photon detection, and ion injection efficiencies, and more economical running costs. The upgraded Shanghai-EBIT is made almost entirely from Ti instead of stainless steel and achieves a vacuum of less than 10-10 Torr, which helps to minimize the loss of highly changed ions through charge exchange. Meanwhile, a more compact structure and efficient cryogenic system, and excellent optical alignment have been of satisfactory. The magnetic field in the central trap region can reach up till 4.8 T with a uniformity of 2.77 × 10-4. So far the upgraded Shanghai-EBIT has been operated up to an electron energy of 151 keV and a beam current of up to 218 mA, although promotion to even higher energy is still in progress. Radiation from ions as highly charged as Xe53+, 54+ has been produced and the characterization of current density is estimated from the measured electron beam width.

  19. Upgrade of the electron beam ion trap in Shanghai

    SciTech Connect

    Lu, D.; Yang, Y.; Xiao, J.; Shen, Y.; Fu, Y.; Wei, B.; Yao, K.; Hutton, R.; Zou, Y.

    2014-09-15

    Over the last few years the Shanghai electron beam ion trap (EBIT) has been successfully redesigned and rebuilt. The original machine, developed under collaboration with the Shanghai Institute of Applied Physics, first produced an electron beam in 2005. It could be tuned with electron energies between 1 and 130 keV and beam current up to 160 mA. After several years of operation, it was found that several modifications for improvements were necessary to reach the goals of better electron optics, higher photon detection, and ion injection efficiencies, and more economical running costs. The upgraded Shanghai-EBIT is made almost entirely from Ti instead of stainless steel and achieves a vacuum of less than 10{sup −10} Torr, which helps to minimize the loss of highly changed ions through charge exchange. Meanwhile, a more compact structure and efficient cryogenic system, and excellent optical alignment have been of satisfactory. The magnetic field in the central trap region can reach up till 4.8 T with a uniformity of 2.77 × 10{sup −4}. So far the upgraded Shanghai-EBIT has been operated up to an electron energy of 151 keV and a beam current of up to 218 mA, although promotion to even higher energy is still in progress. Radiation from ions as highly charged as Xe{sup 53+,} {sup 54+} has been produced and the characterization of current density is estimated from the measured electron beam width.

  20. 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.

  1. BEAM LOSS ESTIMATES AND CONTROL FOR THE BNL NEUTRINO FACILITY.

    SciTech Connect

    WENG, W.-T.; LEE, Y.Y.; RAPARIA, D.; TSOUPAS, N.; BEEBE-WANG, J.; WEI, J.; ZHANG, S.Y.

    2005-05-16

    The requirement for low beam loss is very important both to protect the beam component, and to make the hands-on maintenance possible. In this report, the design considerations to achieving high intensity and low loss will be presented. We start by specifying the beam loss limit at every physical process followed by the proper design and parameters for realizing the required goals. The process considered in this paper include the emittance growth in the linac, the H{sup -} injection, the transition crossing, the coherent instabilities and the extraction losses.

  2. A Flexible, Low Cost, Beam Loss Monitor Evaluation System

    SciTech Connect

    Hoyes, George Garnet; Pimol, Piti; Juthong, Nawin; Attaphibal, Malee

    2007-01-19

    A flexible, low cost, Beam Loss Monitor (BLM) Evaluation System based on Bergoz BLMs has been developed. Monitors can easily be moved to any location for beam loss investigations and/or monitor usefulness evaluations. Different PC pulse counting cards are compared and tested for this application using the display software developed based on LabVIEW. Beam problems uncovered with this system are presented.

  3. Observations of fast ion losses due to toroidal Alfven eigenmodes in TFTR

    SciTech Connect

    Darrow, D.S.; Zweben, S.J.; Chang, Z.

    1993-08-01

    In a tokamak, knowledge of the rate of fast ion loss is of importance in determining the energy balance of the discharge. Heating of the discharge may be diminished if losses are significant, since neutral beam ions, ICRF heating tail ions, and alpha particles all heat the plasma and may all be lost through processes which expel fast ions. In addition, a loss of fast ions which is sufficiently intense and localized may damage plasma facing components in the vacuum vessel. For these reasons, knowledge of the fast ion loss mechanisms is desirable. Loss processes for fast ions in a tokamak fit into two broad categories: single particle and collective. Single particle losses are those, such as first orbit loss, which are independent of the number of fast ions present. These have been seen in numerous instances on TFIR with DD fusion products, and are reported elsewhere. Collective losses arise when the fast ion density is sufficient to drive instabilities which then cause loss. The drive can come from {partial_derivative}f{sub fi}/{partial_derivative}{psi} (where f{sub fi} is the fast ion distribution function), {partial_derivative}f{sub fi}/{partial_derivative}E, and resonances. Examples of collective instabilities include the toroidal Alfven eigenmode (TAE), the kinetic ballooning mode, alpha driven sawteeth, alpha driven fishbones, Alfven waves, and ion cyclotron waves. This paper limits itself to the presentation of observations made during what are believed to be TAEs which were excited under two conditions in TFTR: at low field (1.5 T), with neutral beam ions driving the mode, and at intermediate field (3.4 T) with the hydrogen minority ICRF tail ions driving the mode.

  4. Near midplane scintillator-based fast ion loss detector on DIII-D

    SciTech Connect

    Chen, X.; Heidbrink, W. W.; Fisher, R. K.; Pace, D. C.; Chavez, J. A.; Van Zeeland, M. A.; Garcia-Munoz, M.

    2012-10-15

    A new scintillator-based fast-ion loss detector (FILD) installed near the outer midplane of the plasma has been commissioned on DIII-D. This detector successfully measures coherent fast ion losses produced by fast-ion driven instabilities ({<=}500 kHz). Combined with the first FILD at {approx}45 Degree-Sign below the outer midplane [R. K. Fisher, et al., Rev. Sci. Instrum. 81, 10D307 (2010)], the two-detector system measures poloidal variation of losses. The phase space sensitivity of the new detector (gyroradius r{sub L}{approx}[1.5-8] cm and pitch angle {alpha}{approx}[35 Degree-Sign -85 Degree-Sign ]) is calibrated using neutral beam first orbit loss measurements. Since fast ion losses are localized poloidally, having two FILDs at different poloidal locations allows for the study of losses over a wider range of plasma shapes and types of loss orbits.

  5. Resonant Ionization Laser Ion Source for Radioactive Ion Beams

    SciTech Connect

    Liu, Yuan; Beene, James R; Havener, Charles C; Vane, C Randy; Gottwald, T.; Wendt, K.; Mattolat, C.; Lassen, J.

    2009-01-01

    A resonant ionization laser ion source based on all-solid-state, tunable Ti:Sapphire lasers is being developed for the production of pure radioactive ion beams. It consists of a hot-cavity ion source and three pulsed Ti:Sapphire lasers operating at a 10 kHz pulse repetition rate. Spectroscopic studies are being conducted to develop ionization schemes that lead to ionizing an excited atom through an auto-ionization or a Rydberg state for numerous elements of interest. Three-photon resonant ionization of 12 elements has been recently demonstrated. The overall efficiency of the laser ion source measured for some of these elements ranges from 1 to 40%. The results indicate that Ti:Sapphire lasers could be well suited for laser ion source applications. The time structures of the ions produced by the pulsed lasers are investigated. The information may help to improve the laser ion source performance.

  6. Beam Loss Studies for the 2-MW LBNE Proton Beam Line

    SciTech Connect

    Drozhdin, A.I.; Childress, S.R.; Mokhov, N.V.; Tropin, I.S.; Zwaska, R.; /Fermilab

    2012-05-01

    Severe limits are put on allowable beam loss during extraction and transport of a 2.3 MW primary proton beam for the Long Baseline Neutrino Experiment (LBNE) at Fermilab. Detailed simulations with the STRUCT and MARS codes have evaluated the impact of beam loss of 1.6 x 10{sup 14} protons per pulse at 120 GeV, ranging from a single pulse full loss to sustained small fractional loss. It is shown that loss of a single beam pulse at 2.3 MW will result in a catastrophic event: beam pipe destruction, damaged magnets and very high levels of residual radiation inside and outside the tunnel. Acceptable beam loss limits have been determined and robust solutions developed to enable efficient proton beam operation under these constraints.

  7. 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.

  8. Probe measurements in ion-beam plasma

    SciTech Connect

    Dudin, S.V.

    1994-12-31

    The particularities of the electric probe measurements in the ion-beam plasma (IBP) have been investigated. To find the electron density n{sub e} and temperature T{sub c} as well as electron energy distribution it is necessary to separate electron current from full probe current, because ion part of this current is often large enough to mask the electron part. According to collisionless probe theory, radius of ion layer in strongly non-isothermal plasma (as in their case) and consequently the ion current are determined by Child`s law. However, at presence of ion beam with high enough energy {var_epsilon}{sub b} >> e{var_phi}{sub p}, this law is broken. The author has found the dependence of Langmuir probe ion current I{sub i} on probe potential {var_phi}{sub p} at presence of IB. The constant ion density approach was used in cylindrical and spherical geometry of the probe layer. Dependence of ion current founded experimentally accords with Child`s law when the probe is placed outside the beam and linear--within the beam. Application of only the chemical Langmuir probe is insufficient for energoanalysis of IBP electrons because of ion current interference. To solve this problem combination of the techniques of cylindrical probe, large plate probe (5 x 5mm) and two-grid energoanalyzer was used. Design and parameters of the two-grid analyzer are presented. Measuring system is described for determination of electron energy distribution function in low temperature plasma by double differentiation of the electric probe volt-ampere characteristic by modulation method.

  9. 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.

  10. Beam Loss Monitors for NSLS-II Storage Ring

    SciTech Connect

    Kramer, S.L.; Cameron, P.

    2011-03-28

    The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two cells of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. To measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber (VC) wall. This will be done using the Cerenkov light as electrons transit ultra-pure fused silica rods placed close to the inner edge of the VC. The entire length of the rod will collect light from the electrons of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

  11. 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.

  12. Plasma focus ion beam-scaling laws

    NASA Astrophysics Data System (ADS)

    Saw, S. H.

    2014-08-01

    Measurements on plasma focus ion beams include various advanced techniques producing a variety of data which has yet to produce benchmark numbers. Recent numerical experiments using an extended version of the Lee Code has produced reference numbers and scaling trends for number and energy fluence of deuteron beams as functions of stored energy E0. At the pinch exit the ion number fluence (ions m-2) and energy fluence (J m-2) computed as 2.4-7.8×1020 and 2.2-33×106 respectively were found to be independent of E0 from 0.4 - 486 kJ. This work was extended to the ion beams for various gases. The results show that, for a given plasma focus, the fluence, flux, ion number and ion current decrease from the lightest to the heaviest gas except for trend-breaking higher values for Ar fluence and flux. The energy fluence, energy flux, power flow and damage factors are relatively constant from H2 to N2 but increase for Ne, Ar, Kr and Xe due to radiative cooling and collapse effects. This paper reviews this work and in a concluding section attempts to put the accumulating large amounts of data into the form of a scaling law of beam energy Ebeam versus storage energy E0 taking the form for deuteron as: {Ebeam} = 18.2{E}01.23; where Ebeam is in J and E0 is in kJ. It is hoped that the establishment of such scaling laws places on a firm footing the reference quantitative ideas for plasma focus ion beams.

  13. High-powered pulsed-ion-beam acceleration and transport

    SciTech Connect

    Humphries, S. Jr.; Lockner, T.R.

    1981-11-01

    The state of research on intense ion beam acceleration and transport is reviewed. The limitations imposed on ion beam transport by space charge effects and methods available for neutralization are summarized. The general problem of ion beam neutralization in regions free of applied electric fields is treated. The physics of acceleration gaps is described. Finally, experiments on multi-stage ion acceleration are summarized.

  14. Beam Control for Ion Induction Accelerators

    SciTech Connect

    Sangster, T.C.; Ahle, L.

    2000-02-17

    Coordinated bending and acceleration of an intense space-charge-dominated ion beam has been achieved for the first time. This required the development of a variable waveform, precision, bi-polar high voltage pulser and a precision, high repetition rate induction core modulator. Waveforms applied to the induction cores accelerate the beam as the bi-polar high voltage pulser delivers a voltage ramp to electrostatic dipoles which bend the beam through a 90 degree permanent magnet quadrupole lattice. Further work on emittance minimization is also reported.

  15. 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.

  16. Beam Loss Control for the NSLS-II Storage Ring

    SciTech Connect

    Kramer, S.L.; Choi, J.

    2011-03-28

    The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for {le} 10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region.

  17. Ion-chamber-based loss monitor system for the Los Alamos Meson Physics Facility

    SciTech Connect

    Plum, M.A.; Brown, D.; Browman, A.; Macek, R.J.

    1995-05-01

    A new loss monitor system has been designed and installed at the Los Alamos Meson Physics Facility (LAMPF). The detectors are ion chambers filled with N{sub 2} gas. The electronics modules have a threshold range of 1:100, and they can resolve changes in beam loss of about 2% of the threshold settings. They can generate a trip signal in 2 {mu}s if the beam loss is large enough; if the response time of the Fast Protect System is included the beam will be shut off in about 37 {mu}s.

  18. Beam dynamics in heavy ion fusion

    SciTech Connect

    Seidl, P.

    1995-04-01

    A standard design for heavy ion fusion drivers under study in the US is an induction linac with electrostatic focusing at low energy and magnetic focusing at higher energy. The need to focus the intense beam to a few-millimeter size spot at the deuterium-tritium target establishes the emittance budget for the accelerator. Economic and technological considerations favor a larger number of beams in the low-energy, electrostatic-focusing section than in the high-energy, magnetic-focusing section. Combining four beams into a single focusing channel is a viable option, depending on the growth in emittance due to the combining process. Several significant beam dynamics issues that are, or have been, under active study are discussed: large space charge and image forces, beam wall clearances, halos, alignment, longitudinal instability, and bunch length control.

  19. 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.

  20. Production of highly charged ion beams from ECR ion sources

    SciTech Connect

    Xie, Z.Q.

    1997-09-01

    Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 e{mu}A of O{sup 7+} and 1.15 emA of O{sup 6+}, more than 100 e{mu}A of intermediate heavy ions for charge states up to Ar{sup 13+}, Ca{sup 13+}, Fe{sup 13+}, Co{sup 14+} and Kr{sup 18+}, and tens of e{mu}A of heavy ions with charge states to Kr{sup 26+}, Xe{sup 28+}, Au{sup 35+}, Bi{sup 34+} and U{sup 34+} have been produced from ECR ion sources. At an intensity of at least 1 e{mu}A, the maximum charge state available for the heavy ions are Xe{sup 36+}, Au{sup 46+}, Bi{sup 47+} and U{sup 48+}. An order of magnitude enhancement for fully stripped argon ions (I {ge} 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams.

  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. 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.

  3. 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.

  4. 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

  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. Graphene engineering by neon ion beams

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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. 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.

  9. Electron beam ion sources and traps (invited)

    NASA Astrophysics Data System (ADS)

    Becker, Reinard

    2000-02-01

    The electron beam method of stepwise ionization to highest charge states has found applications in electron beam ion sources (EBISs) for accelerators and atomic physics collision experiments as well as in electron beam ion traps (EBITs) for x-ray and mass spectroscopy. A dense and almost monoenergetic electron beam provides a unique tool for ionization, because radiative recombination by slow electrons is negligible and charge exchange is almost avoided in ultrahigh vacua. These are essential differences to electron cyclotron resonance ion sources with inevitable low energy electrons and comparatively high gas pressure. The distinction between EBIS and EBIT as genuine devices has become meaningless, because EBISs may work as traps and almost all EBITs are feeding beamlines for external experiments. More interesting is to note the diversification of these devices, which demonstrates that a matured technology is finding dedicated answers for different applications. At present we may distinguish six major lines of development and application: high current EBISs for upcoming hadron colliders, super EBITs in the energy range above 300 keV for quantum electrondynamics tests, inexpensive and small EBISTs for atomic physics studies, a highly efficient EBIS with oscillating electrons, MEDEBIS for tumor therapy with C6+, and charge breeding in facilities for exotic radioactive beams.

  10. Storage rings for radioactive ion beams

    NASA Astrophysics Data System (ADS)

    Nolden, F.; Dimopoulou, C.; Dolinskii, A.; Steck, M.

    2008-10-01

    Storage rings for radioactive heavy ions can be applied for a wide range of experiments in atomic and nuclear physics. The rare isotope beams are produced in flight via fragmentation or fission of high-intensity primary ions and they circulate in the storage ring at moderately relativistic energies (typically between 0.1 GeV/u up to 1 GeV/u). Due to their production mechanism they are usually highly charged or even fully stripped. The circulating radioactive heavy ion beams can be used to measure nuclear properties such as masses and decay times, which, in turn, can depend strongly on the ionic charge state. The storage rings must have large acceptances and dynamic apertures. The subsequent application of stochastic precooling of the secondary ions which are injected with large transverse and longitudinal emittances, and electron cooling to reach very high phase space densities has turned out to be a helpful tool for experiments with short-lived ions having lifetimes down to a few seconds. Some of these experiments have already been performed at the experimental storage ring ESR at GSI. The storage ring complex of the FAIR project is intended to enhance significantly the range of experimental possibilities. It is planned to extend the scope of experimental possibilities to collisions with electron or antiproton beams.