Journal articles: 'Ion Beam Physik'

1

Alani, R., and P. R. Swann. "Chemically assisted ion-beam etching in a low-angle ion mill." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 718–19. http://dx.doi.org/10.1017/s0424820100149428.

Full text

Abstract:

In conventional ion mills, chemically assisted ion beam etching (CAIBE) has become an establish method for TEM specimen preparation of certain materials. CAIBE employs a reactive gas which brought in contact with the specimen through a jet assembly, while an inert gas ion beam is directed on the same area. Therefore, thinning occurs by the combination of chemical reaction and physic sputtering, which leads to enhanced thinning rates. The reactive gas used in the CAIBE technique can generated from a solid source which sublimes e.g. iodine or it can be injected directly from a pressuriz gas bottle e.g. nitrous oxide. Nitrous oxide in combination with a xenon ion beam has been used from cross sectioning TEM specimens of diamond films on silicon.It is well known that indium-containing compound semiconductors develop indium islands on the surface when thinned with an argon ion beam. It is believed that preferential sputtering enriches the surface with indium and that heating by the ion beam melts the indium which then agglomerates to for small globules on the surface.

APA, Harvard, Vancouver, ISO, and other styles

2

Mark, James W. K. "Recent Livermore research on ion beam fusion targets: Utilization of direct-drive efficiency during optimization of symmetry and utilization of polarized DT fuel." Laser and Particle Beams 9, no. 3 (September 1991): 713–23. http://dx.doi.org/10.1017/s0263034600003724.

Full text

Abstract:

We investigated several examples of ion beam targets that utilize the energy efficiency of direct drive while optimizing on the symmetry requirements. Heavy-ion beams of charge state Z ≥ 3 at 5–10 GeV have ≲15–20 m bending radii with 3.5-T fields. Beams like these could be used with targets involving direct drive. Control of asymmetries in direct-drive ion beam targets depends on control of the effects of residual target asymmetries after an appropriate illumination scheme has been adopted. In this paper, we outline results of our investigations into ion beam target concepts in which the effects of residual asymmetries are ameliorated. The beams are placed according to our axially symmetric Gaussian-quadrature illumination scheme (Mark 1986). The targets survive the effects of residual asymmetries in our recent 2-D hydrodynamic simulations. We also briefly discuss the additional positive effects of polarized DT fuel on ion beam targets.

APA, Harvard, Vancouver, ISO, and other styles

3

BADZIAK, J., S. GŁOWACZ, S. JABŁOŃSKI, P. PARYS, J. WOŁOWSKI, and H. HORA. "Laser-driven generation of high-current ion beams using skin-layer ponderomotive acceleration." Laser and Particle Beams 23, no. 4 (October 2005): 401–9. http://dx.doi.org/10.1017/s0263034605050573.

Full text

Abstract:

Basic properties of generation of high-current ion beams using the skin-layer ponderomotive acceleration (S-LPA) mechanism, induced by a short laser pulse interacting with a solid target are studied. Simplified scaling laws for the ion energies, the ion current densities, the ion beam intensities, and the efficiency of ions' production are derived for the cases of subrelativistic and relativistic laser-plasma interactions. The results of the time-of-flight measurements performed for both backward-accelerated ion beams from a massive target and forward-accelerated beams from a thin foil target irradiated by 1-ps laser pulse of intensity up to ∼ 1017 W/cm2 are presented. The ion current densities and the ion beam intensities at the source obtained from these measurements are compared to the ones achieved in recent short-pulse experiments using the target normal sheath acceleration (TNSA) mechanism at relativistic (>1019 W/cm2) laser intensities. The possibility of application of high-current ion beams produced by S-LPA at relativistic intensities for fast ignition of fusion target is considered. Using the derived scaling laws for the ion beam parameters, the achievement conditions for ignition of compressed DT fuel with ion beams driven by ps laser pulses of total energy ≤ 100 kJ is shown.

APA, Harvard, Vancouver, ISO, and other styles

4

Ter-Avetisyan, S., M. Schnürer, R. Polster, P. V. Nickles, and W. Sandner. "First demonstration of collimation and monochromatisation of a laser accelerated proton burst." Laser and Particle Beams 26, no. 4 (November 17, 2008): 637–42. http://dx.doi.org/10.1017/s0263034608000712.

Full text

Abstract:

AbstractLaser produced ion beams have a large divergence angle and a wide energy spread. To our knowledge, this is the first demonstration of collimation and monochromatisation of laser accelerated proton beams, using a permanent quadrupole magnet lens system. It acts as a tunable band pass filter by collimating or focusing the protons with the same energy. Because it gathers nearly the whole proton emission, a strong enhancement of the beam density appears. For the collimated beam, an increase of the proton density in the (3.7 ± 0.3) MeV energy band up to a factor of ~30, from possible 40, relative to the non-collimated beam is demonstrated. With the help of this simple, reliable, and well established technique new perspectives will be opened for science and technology, monoenergetic ion beams can be attained in any lab, where a source of laser accelerated ions exist. This finding enables to apply afterward well known beam steering techniques to the formed ion beam, which are applied in conventional accelerators to manipulate the beam parameters or to transport the beams and make them use in many application.

APA, Harvard, Vancouver, ISO, and other styles

5

Dietrich, K. G., K. Mahrt-Olt, J. Jacoby, E. Boggasch, M. Winkler, B. Heimrich, and D. H. H. Hoffmann. "Beam–plasma interaction experiments with heavy-ion beams." Laser and Particle Beams 8, no. 4 (December 1990): 583–93. http://dx.doi.org/10.1017/s0263034600009010.

Full text

Abstract:

The progress of the experimental research program at GSI for studying beam-plasma interaction phenomena is reported. Heavy-ion beams from the new accelerator facility SIS/ESR at GSI-Darmstadt are now available for experiments, and will soon deliver ≥ 109 particles per pulse in 100 ns. Focused on a small sample of matter, the beams will be able to produce a high-density plasma and to permit investigation of interaction processes of heavy ions with hot ionized matter.For the intense beam from the new heavy-ion synchrotron (SIS), a fine-focus system has been designed to produce a high specific deposition power beam for target experiments with a beam-spot radius of 100 μm. We further discuss improvements of this lens system by nonconventional focusing devices such as plasma lenses.Intense-beam experiments at the RFQ Maxilac accelerator at GSI have already produced the first heavy-ion-induced plasma with a temperature of 0.75 eV. New diagnostic techniques for investigating ion-beam-induced plasmas are presented. The low-intensity beam from the GSI UNILAC has been used to measure energy deposition profiles of heavy ions in hot ionized matter. In this experiment an enhancement of the stopping power for heavy ions was observed. The current experimental research program tests basic plasma theory and addresses key issues of inertial confinement fusion driven by intense heavy-ion beams.

APA, Harvard, Vancouver, ISO, and other styles

6

Hu, Zhang-Hu, Yuan-Hong Song, Yong-Tao Zhao, and You-Nian Wang. "Modulation of continuous ion beams with low drift velocity by induced wakefield in background plasmas." Laser and Particle Beams 31, no. 1 (February 1, 2013): 135–40. http://dx.doi.org/10.1017/s0263034612001115.

Full text

Abstract:

AbstractTwo-dimensional particle-in-cell simulations are performed to investigate the propagation of low energy continuous ion beams through background plasmas. It is shown that the continuous ion beam can be modulated into periodic short beam pulses by the induced wakefield, which can be adopted as a method to produce ultrashort ion beam pulses. Furthermore, the transport of the continuous ion beam in plasma with density gradient in the beam propagation direction is proposed and an enhanced longitudinal compression by density gradient is found due to the phase lock of ion pulses in the focusing regions of wakefield and reduced heating of plasma electrons.

APA, Harvard, Vancouver, ISO, and other styles

7

SINGH, D. P., O. N. AWASTHI, and V. PALLESCHI. "An analytic model of coupling of intense ion beams with spherical plasma target." Laser and Particle Beams 18, no. 1 (January 2000): 21–24. http://dx.doi.org/10.1017/s0263034600181030.

Full text

Abstract:

The hydrodynamics of plasma ablation and the thermalization process of the target interior core with the surrounding corona, formed by the uniform irradiation of intense ion beams over the spherical target are investigated in detail. Starting from the basic equations for the ion beam, the ion beam penetration depth is calculated and the self-regulation condition for the hot corona is applied to describe the process of core-corona coupling. The effects of ion beam energy, ion beam mass, and the target electron density on the ion beam penetration depth are studied. As the relevant calculations reveal, it is interesting to note the existence of an optimum value of ion beam energy for which the core-corona coupling attains maximum value, beyond which further increase of the ion beam energy leads to the formation of more tenuous corona only and the target interior core begins to decouple from the surrounding corona.

APA, Harvard, Vancouver, ISO, and other styles

8

Koga, J., J. L. Geary, T. Fujinami, B. S. Newberger, T. Tajima, and N. Rostoker. "Numerical investigation of a plasma beam entering transverse magnetic fields." Journal of Plasma Physics 42, no. 1 (August 1989): 91–110. http://dx.doi.org/10.1017/s0022377800014203.

Full text

Abstract:

We study plasma-beam injection into transverse magnetic fields using both electrostatic and electromagnetic particle-in-cell (PIC) codes. In the case of small beam momentum or energy (low drift kinetic β) we study both large- and small-ion-gyroradius beams. Large-ion-gyroradius beams with a large dielectric constant ε ≫ (M/m)½ are found to propagate across the magnetic field via E × B drifts at nearly the initial injection velocity, where and M/m is the ion-to-electron mass ratio. Beam degradation and undulations are observed, in agreement with previous experimental and analytical results. When ε is of order (M/m)½ the plasma beam propagates across field lines at only half its initial velocity and loses its coherent structure. When ε is much less than (M/m)½ the beam particles decouple at the magnetic field boundary, scattering the electrons and slightly deflecting the ions. For small-ion-gyroradius beam injection a flute-type instability is observed at the beam-magnetic-field interface. In the case of large beam momentum or energy (high drift kinetic β) we observe good penetration of a plasma beam by shielding the magnetic field from the interior of the beam (diamagnetism). However, we observe anomalously fast penetration of the magnetic field into the beam and find that the diffusion rate depends on the electron gyroradius of the beam.

APA, Harvard, Vancouver, ISO, and other styles

9

Niu, K., P. Mulser, and L. Drska. "Beam generations of three kinds of charged particles." Laser and Particle Beams 9, no. 1 (March 1991): 149–65. http://dx.doi.org/10.1017/s0263034600002391.

Full text

Abstract:

Analyses are given for beam generations of three kinds of charged particles: electrons, light ions, and heavy ions. The electron beam oscillates in a dense plasma irradiated by a strong laser light. When the frequency of laser light is high and its intensity is large, the acceleration of oscillating electrons becomes large and the electrons radiate electromagnetic waves. As the reaction, the electrons feel a damping force, whose effect on oscillating electron motion is investigated first. Second, the electron beam induces the strong electromagnetic field by its self-induced electric current density when the electron number density is high. The induced electric field reduces the oscillation motion and deforms the beam.In the case of a light ion beam, the electrostatic field, induced by the beam charge, as well as the electromagnetic field, induced by the beam current, affects the beam motion. The total energy of the magnetic field surrounding the beam is rather small in comparison with its kinetic energy.In the case of heavy ion beams the beam charge at the leading edge is much smaller in comparison with the case of light ion beams when the heavy ion beam propagates in the background plasma. Thus, the induced electrostatic and electromagnetic fields do not much affect the beam propagation.

APA, Harvard, Vancouver, ISO, and other styles

10

Quintenz, J. P., D. B. Seidel, M. L. Kiefer, T. D. Pointon, R. S. Coats, S. E. Rosenthal, T. A. Mehlhorn, M. P. Desjarlais, and N. A. Krall. "Simulation codes for light-ion diode modeling." Laser and Particle Beams 12, no. 2 (June 1994): 283–324. http://dx.doi.org/10.1017/s0263034600007746.

Full text

Abstract:

The computational tools used in the investigation of light-ion diode physics at Sandia National Laboratories are described. Applied-B ion diodes are used to generate intense beams of ions and focus these beams onto targets as part of Sandia's inertial confinement fusion program. Computer codes are used to simulate the energy storage and pulse forming sections of the accelerator and the power flow and coupling into the diode where the ion beam is generated. Other codes are used to calculate the applied magnetic field diffusion in the diode region, the electromagnetic fluctuations in the anode-cathode gap, the subsequent beam divergence, the beam propagation, and response of various beam diagnostics. These codes are described and some typical results are shown.

APA, Harvard, Vancouver, ISO, and other styles

11

Yatsui, Kiyoshi. "Industrial applications of pulse power and particle beams." Laser and Particle Beams 7, no. 4 (November 1989): 733–41. http://dx.doi.org/10.1017/s0263034600006200.

Full text

Abstract:

An overview is given of recent progress in the industrial applications of intense pulse power and associated particle beams, except for activities in inertial confinement fusion. In particular, several topics are discussed which relate to the applications in the R&D of materials, the excitation of short wavelength lasers, the generation of charged particle beams, and the development of plasma X-ray sources.I. Applications in material processing. If intense pulsed charged particle beams are directed onto materials, only their surfaces where the beam energy is deposited are quickly heated up to very high temperatures. Using the pulsed beam in this way, we might expect to apply them in R&D of materials. Several novel attempts have been made, e.g., on the preparation of thin films by use of a high-density high-temperature plasma, surface modification by surface heating, and ion-beam mixing of multi-layers by use of the focused electron or ion beams, and so on. Furthermore, experimental studies have been done on the surface modification by ion implantation and the evaluation of the damage due to the irradiation by ion beams.II. Applications in the excitation of short wavelength lasers. Activities in the excitation of high-power, short wavelength lasers by using electron beams or ion beams have increased considerably.III. Applications in the generation of charged particle beams, and the development of plasma X-ray source. With regard to new accelerator technologies, several attempts are underway on the application of the modified betatron or the development of a convergent electron beam accelerator with a plasma cathode.

APA, Harvard, Vancouver, ISO, and other styles

12

PEGORARO, F., S. ATZENI, M. BORGHESI, S. BULANOV, T. ESIRKEPOV, J. HONRUBIA, Y. KATO, et al. "Production of ion beams in high-power laser–plasma interactions and their applications." Laser and Particle Beams 22, no. 1 (March 2004): 19–24. http://dx.doi.org/10.1017/s0263034604221048.

Full text

Abstract:

Energetic ion beams are produced during the interaction of ultrahigh-intensity, short laser pulses with plasmas. These laser-produced ion beams have important applications ranging from the fast ignition of thermonuclear targets to proton imaging, deep proton lithography, medical physics, and injectors for conventional accelerators. Although the basic physical mechanisms of ion beam generation in the plasma produced by the laser pulse interaction with the target are common to all these applications, each application requires a specific optimization of the ion beam properties, that is, an appropriate choice of the target design and of the laser pulse intensity, shape, and duration.

APA, Harvard, Vancouver, ISO, and other styles

13

Okamura, Masahiro, Megumi Sekine, Shunsuke Ikeda, Takeshi Kanesue, Masafumi Kumaki, and Yasuhiro Fuwa. "Preliminary result of rapid solenoid for controlling heavy-ion beam parameters of laser ion source." Laser and Particle Beams 33, no. 2 (March 13, 2015): 137–41. http://dx.doi.org/10.1017/s026303461500004x.

Full text

Abstract:

AbstractTo realize a heavy-ion inertial fusion (HIF) driver, we have studied a possibility of laser ion source (LIS). A LIS can provide high-current high-brightness heavy-ion beams; however, it was difficult to manipulate the beam parameters. To overcome the issue, we employed a pulsed solenoid in the plasma drift section and investigated the effect of the solenoid field on singly charged iron beams. The rapid ramping magnetic field could enhance limited time slice of the current and simultaneously the beam emittance changed accordingly. This approach may also be useful to realize an ion source for HIF power plant.

APA, Harvard, Vancouver, ISO, and other styles

14

Wong, Chiow San, and S. L. Yap. "Generation of Deuteron Beam from the Plasma Focus." Solid State Phenomena 107 (October 2005): 151–0. http://dx.doi.org/10.4028/www.scientific.net/ssp.107.151.

Full text

Abstract:

The generation of deuteron beam from a 3 kJ Mather type plasma focus is studied. Two simple ion collectors made of copper plates are employed and are placed at the axis of the electrodes to detect the ion beam. The deuteron beam intensity at various deuterium gas pressures is determined together with ion beam energy using the time of flight method. For a series of discharges of the present plasma focus system operated at 15 kV discharge voltage, ion beams of energies ranging from 50 to 200 keV have been measured. The suitable deuterium filling pressure for ion beam production for electrodes lengths of 16 cm, 22 cm and 27 cm are 1 mbar, 0.7 mbar and 0.5 mbar respectively.

APA, Harvard, Vancouver, ISO, and other styles

15

Bieniosek, F. M., E. Henestroza, and P. Ni. "Funnel cone for focusing intense ion beams on a target." Laser and Particle Beams 28, no. 1 (March 2010): 209–14. http://dx.doi.org/10.1017/s0263034610000108.

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

16

Bluhm, H. J., G. Keßler, and R. R. Petersen. "Light ion beam driven inertial confinement fusion: Requirements and achievements." Laser and Particle Beams 14, no. 4 (December 1996): 655–63. http://dx.doi.org/10.1017/s0263034600010375.

Full text

Abstract:

In this paper we compare the requirements for a light ion beam driven inertial confinement fusion (ICF) reactor with the present achievements in pulsed power technology, ion diode performance, beam transport, and target physics. The largest gap exists in beam quality and repetition rate capability of high-power ion diodes. Beam quality can very likely be improved to a level sufficient for driving a single-shot ignition facility, if the potential of two-stage acceleration is used. Present schemes for repetition rate ion diodes allow either too low power densities or create too large beam divergence. On the other hand, repetitively operating pulsed-power generators meeting the requirements for an ICF reactor driver can be built with present technology. Also, a rather mature target concept has been developed for indirect drive with light ion beams.

APA, Harvard, Vancouver, ISO, and other styles

17

Ulrich, A., B. Busch, W. Krötz, G. Ribitzki, J. Wieser, and D. E. Murnick. "Heavy-ion beam pumping as a model for nuclear-pumped lasers." Laser and Particle Beams 11, no. 3 (September 1993): 509–19. http://dx.doi.org/10.1017/s0263034600005164.

Full text

Abstract:

Heavy-ion accelerators can provide various beams from protons to uranium ions with energies ranging from a few keV/u to more than 1 GeV/u. The Munich Tandem van de Graaff accelerator has been used for most of the experiments described in this article. It can provide continuous or pulsed beams of almost all elements with particle energies of about 3.5 MeV/u. The pulse width is typically 2 ns. Maximum DC-beam currents of the order of 10 μA can be obtained, for example, for 32S ions. When the beam is focused to a beam spot of about 3 mm diameter, the flux of the ions is comparable to the flux of fission fragments used for nuclear-pumped lasers. Ion beam pumping is therefore well suited for model experiments of nuclear-pumped lasers. Technical aspects of ion beam-pumped lasers are discussed and the results of the lasers that have thus far been pumped by this method aresummarized. As ion beams are available either continuous or at high-pulse repetition rates ranging from tens of kHz to MHz, detailed spectroscopic and time-resolved studies of the emission of light induced by heavy-ion excitation of the target material can easily be performed. Experiments in which the emission by rare gas excimers and line radiation from atoms and ions has been studied are described. Lifetime measurements of excited levels at different target densities were used to measure collisional rate constants.

APA, Harvard, Vancouver, ISO, and other styles

18

NEFF, S., R. KNOBLOCH, D. H. H. HOFFMANN, A. TAUSCHWITZ, and S. S. YU. "Transport of heavy-ion beams in a 1 m free-standing plasma channel." Laser and Particle Beams 24, no. 1 (March 2006): 71–80. http://dx.doi.org/10.1017/s0263034606060125.

Full text

Abstract:

The transport of high-current heavy-ion beams in plasma channels is a promising option for the final transport in a heavy-ion fusion reactor, since it simplifies the construction of the reactor chamber significantly. Our experiments at the Gesellschaft für Schwerionenforschung demonstrate the creation of 1 m long stable plasma channels and the transport of heavy-ion beams. The article outlines the experimental setup used at GSI and reports the results of beam transport measurements using these long channels. The experiments demonstrate good beam transport properties of the channel, indicating that channel transport is a viable alternative to neutralized-ballistic transport.

APA, Harvard, Vancouver, ISO, and other styles

19

Pozimski, J., and M. Aslaninejad. "Gabor lenses for capture and energy selection of laser driven ion beams in cancer treatment." Laser and Particle Beams 31, no. 4 (October 9, 2013): 723–33. http://dx.doi.org/10.1017/s0263034613000761.

Full text

Abstract:

AbstractThe application of laser accelerated ion beams in Hadron therapy requires ion beam optics with unique features. It has been shown that due to the spectral and spatial distribution of laser accelerated protons a lens based focusing system has advantages over aperture collimated beam formation. We present a compact ion optical system with therapy applications, based on Gabor space charge lenses for collecting, focusing and energy filtering the laser produced proton beam. For a full therapy solution, a scenario based on three space charge lenses is presented. In this very compact beam line an aperture is foreseen for energy selection.

APA, Harvard, Vancouver, ISO, and other styles

20

Träbert, E. "Precise atomic lifetime measurements with stored ion beams and ion traps." Canadian Journal of Physics 80, no. 12 (December 1, 2002): 1481–501. http://dx.doi.org/10.1139/p02-123.

Full text

Abstract:

For many years, atomic lifetime measurements on multiply-charged ions have been done almost exclusively by beam-foil spectroscopy. For low ion charges, however, spin-changing "intercombination" transitions have a rate that renders them too slow for traditional fast-beam techniques. Here ion traps and fast-ion beams have been combined in the concept of heavy-ion storage rings. These devices have permitted not only an extension of intercombination lifetime measurements down to singly charged ions, but they also facilitated similar measurements on electric-dipole forbidden transitions. The electron-beam ion trap (EBIT) complements the storage-ring work for work on highly charged ions. Achievements, technical issues, and prospects are outlined. PACS Nos.: 32.70Cs, 32.30Jc, 34.50Fa

APA, Harvard, Vancouver, ISO, and other styles

21

Bozyk, L., D. H. H. Hoffmann, H. Kollmus, and P. Spiller. "Development of a cryocatcher prototype and measurement of cold desorption." Laser and Particle Beams 34, no. 3 (May 4, 2016): 394–401. http://dx.doi.org/10.1017/s0263034616000240.

Full text

Abstract:

AbstractThe superconducting synchrotron SIS100 of the FAIR accelerator project will provide heavy ion beams of highest intensities. SIS100 is the first synchrotron with a special design, optimized for the control of ionization beam loss. Ionization beam loss is the most pronounced loss mechanism at operation with high-intensity, intermediate charge state heavy ions. The new synchrotron layout comprises an ion catcher system, which in combination with a charge separator lattice shall suppress dynamic vacuum effects.A prototype cryogenic ion catcher, including a dedicated cryostat has been designed, manufactured, and tested under realistic conditions with beams from the heavy-ion synchrotron SIS18 at GSI. The gas desorption induced by the impact of heavy ions on this cryocatcher has been measured. For the very first time, a rise of desorption yield with increasing beam energy has been observed. However, measurements at room temperature have confirmed the known decrease of the pressure rise in the investigated energy regime. A transition temperature of 18 K, underneath hydrogen is adsorbed, could be verified several times. The results are significant and used to predict the ionization beam loss at operation of SIS100 at full-beam intensity.

APA, Harvard, Vancouver, ISO, and other styles

22

Citron, A., W. Kühn, A. Rogner, W. Schimassek, and O. Stoltz. "Investigation of a self-magnetically insulated Bθ-diode." Laser and Particle Beams 5, no. 4 (November 1987): 565–72. http://dx.doi.org/10.1017/s0263034600003116.

Full text

Abstract:

An ion diode, where the insulating magnetic Bθ-field is produced by the diode current itself, has been investigated. Using a novel Thomson-parabola spectrometer that is capable of detecting up to 41 beam traces at a single shot and a carbon activation diagnostic the ion beam has been analyzed. The diode, operating at “KALIF”, delivers ion beams of 750 kA at energies of about 0·7 MeV. The focusing version of the diode shows a focus size of 1 cm2, the beam is neutralized to 98–99%, the proton content is about 60%.

APA, Harvard, Vancouver, ISO, and other styles

23

Ulrich, A., B. Busch, H. Eylers, W. Krötz, R. Miller, R. Pfaffenberger, G. Ribitzki, J. Wieser, and D. E. Murnick. "Lasers pumped by heavy-ion beams." Laser and Particle Beams 8, no. 4 (December 1990): 659–77. http://dx.doi.org/10.1017/s0263034600009071.

Full text

Abstract:

General aspects of the excitation of matter with heavy-ion beams are discussed. Lasers in the wavelength region between 1 and 3 μm in rare-gas mixtures pumped with 1.9-GeV xenon, 100-MeV sulphur, 3.6-MeV argon, and 3.3-MeV helium ions are described as examples for lasers pumped by heavy-ion beams. The beam power ranges from a few watts (dc) to about 1 MW during short pulses of about 1-ns length. Optical gain can be measured with an intracavity method. Data on the shape of the volume excited by a 100- MeV 32S beam are shown. An experimental setup for time-resolved optical spectroscopy in a wide wavelength region between a few nanometers and about 700 nm is described. Emission spectra of rare gases excited by heavy-ion beams are discussed and optical gain on ion lines and excimer bands is estimated for different target and beam parameters. Collisional processes in the target gas were studied by time-resolved optical spectroscopy. Population densities of selected 3p levels in Ne I, II, and IV and rate constants for collisional depopulation of excited levels were determined. Experiments planned at the heavy-ion synchrotron SIS at Gesellschaft für Schwerionenforschung in Darmstadt are discussed.

APA, Harvard, Vancouver, ISO, and other styles

24

KASUYA, KOICHI, YOHSUKE KISHI, TAKAHIRO KAMIYA, and MASATO FUNATSU. "Low microdivergence medium-mass ion beam produced from a N2O cryogenic diode." Laser and Particle Beams 19, no. 2 (April 2001): 309–16. http://dx.doi.org/10.1017/s0263034601192207.

Full text

Abstract:

Medium-mass ion beams including nitrogen and oxygen were produced from a cryogenic diode with N2O ice as the ion source. The nominal diode voltage was 300–400 kV, and the peak ion current was 240 A. The beam divergence angle was measured with a five-aperture time-integrated pinhole camera. The five camera images were analyzed to estimate the spatial distribution of the beam source divergence angle along the anode radius, yielding a value of 5–6 mrad for the average microdivergence. This is low enough for this ion source to be studied further in the near future. If possible, we want to consider this as one of the probable candidate ion sources for ion beam drivers for future inertial confinement fusion (ICF) and inertial fusion energy (IFE) applications.

APA, Harvard, Vancouver, ISO, and other styles

25

QIN, HONG, RONALD C. DAVIDSON, EDWARD A. STARTSEV, and W. WEI-LI LEE. "δf simulation studies of the ion–electron two-stream instability in heavy ion fusion beams." Laser and Particle Beams 21, no. 1 (January 2003): 21–26. http://dx.doi.org/10.1017/s0263034602211052.

Full text

Abstract:

Ion–electron two-stream instabilities in high intensity heavy ion fusion beams, described self-consistently by the nonlinear Vlasov–Maxwell equations, are studied using a three-dimensional multispecies perturbative particle simulation method. Large-scale parallel particle simulations are carried out using the recently developed Beam Equilibrium, Stability, and Transport (BEST) code. For a parameter regime characteristic of heavy ion fusion drivers, simulation results show that the most unstable mode of the ion–electron two-stream instability has a dipole-mode structure, and the linear growth rate decreases with increasing axial momentum spread of the beam particles due to Landau damping by the axial momentum spread of the beam ions in the longitudinal direction.

APA, Harvard, Vancouver, ISO, and other styles

26

Han, Sheng, Hong-Ying Chen, Chih-Hsuan Cheng, Jian-Hong Lin, and Han C. Shih. "Aluminum nitride films synthesized by dual ion beam sputtering." Journal of Materials Research 19, no. 12 (December 1, 2004): 3521–25. http://dx.doi.org/10.1557/jmr.2004.0451.

Full text

Abstract:

Aluminum nitride films were deposited by varying the voltages of argon ion beams from 400 to 1200 V in dual ion beam sputtering. The crystal structure, microstructure, and elemental distributions of the aluminum nitride films were analyzed by x-ray diffraction, field emission scanning electron microscopy, and secondary ion mass spectroscopy, respectively. The aluminum nitride films exhibited the 〈002〉 preferred orientation at an optimal ion beam voltage of 800 V. The orientation changed to a mixture of {100} and {002} planes above 800 V, accounting for radiation damage. The thickness of the film increases with increasing ion beam voltage, reaching a steady state value of 210 nm at an ion beam voltage of 1200 V. Under optimal condition (800 V), the c-axis orientation of the aluminum nitride 〈002〉 film was obtained with a dense and high-quality crystal structure.

APA, Harvard, Vancouver, ISO, and other styles

27

Okada, Toshio, and Winfried Schmidt. "Two-stream and filamentation instabilities for a light ion beam—plasma system." Journal of Plasma Physics 37, no. 3 (June 1987): 373–82. http://dx.doi.org/10.1017/s0022377800012253.

Full text

Abstract:

Electrostatic two-stream and electromagnetic filamentation instabilities for a light ion beam penetrating a plasma are investigated. The dispersion relations of these instabilities including the effect of plasma heating by the ion beam are solved analytically and numerically. Stability conditions are derived for propagation through a plasma. Attention is paid to the finite size effects of beams with small diameters of the order 0·1 cm typical for pinched gas discharges. The results are illustrated by plotting stability boundaries for a 100 keV proton beam propagating through a plasma.

APA, Harvard, Vancouver, ISO, and other styles

28

Li, Bo, Xia Xiang, Chengxiang Tian, Chunyuan Hou, Wei Liao, Hongxiang Deng, Xiaolong Jiang, et al. "Anisotropic ion beam etching of fused silica to mitigate subsurface damage." International Journal of Modern Physics B 34, no. 08 (March 27, 2020): 2050060. http://dx.doi.org/10.1142/s0217979220500605.

Full text

Abstract:

The laser damage resistance of fused silica optics depends significantly on the surface quality. In this work, anisotropic etching with inert ion beams at various ion incident angles was performed to investigate the evolution of the fused silica surface. The results show that the surface is smoothed when the incident angle is below [Formula: see text]. However, the fused silica surface starts to become coarse owing to the formation of nanostructures on the surface when the incident angle exceeds [Formula: see text]. Further, ion beam etching at a large incident angle of [Formula: see text] removes subsurface defects and less induces nanostructures, resulting in reduction of the surface roughness. The concentrations of impurities and defects are both significantly reduced after ion beam etching. The surface quality, subsurface and surface defects, and surface impurities determine the variation in the laser damage threshold of fused silica with the ion incident angle. The results demonstrate successful application of ion beam etching to improve the laser damage resistant characteristics of fused silica optics. Ion beam etching is a very versatile tool that provides physical erosion to anisotropically mitigate surface damage of fused silica.

APA, Harvard, Vancouver, ISO, and other styles

29

Ulrich, Andreas. "Light emission from particle beam induced plasma: An overview." Laser and Particle Beams 30, no. 2 (March 13, 2012): 199–205. http://dx.doi.org/10.1017/s0263034611000838.

Full text

Abstract:

AbstractExperiments to study the light emission from plasma produced by particle beams are presented. Fundamental aspects in comparison with discharge plasma formation are discussed. It is shown that the formation of excimer molecules is an important process. This paper summarizes various studies of particle beam induced light emission and presents the first results of a direct comparison of light emission induced by electron- and ion beam excitation. Both high energy heavy ion beam and low energy electron beam experiments are described and an overview over applications in the form of light sources, lasers, and ionization devices is given.

APA, Harvard, Vancouver, ISO, and other styles

30

Klingner, Nico, Gregor Hlawacek, Paul Mazarov, Wolfgang Pilz, Fabian Meyer, and Lothar Bischoff. "Imaging and milling resolution of light ion beams from helium ion microscopy and FIBs driven by liquid metal alloy ion sources." Beilstein Journal of Nanotechnology 11 (November 18, 2020): 1742–49. http://dx.doi.org/10.3762/bjnano.11.156.

Full text

Abstract:

While the application of focused ion beam (FIB) techniques has become a well-established technique in research and development for patterning and prototyping on the nanometer scale, there is still a large underused potential with respect to the usage of ion species other than gallium. Light ions in the range of m = 1–28 u (hydrogen to silicon) are of increasing interest due to the available high beam resolution in the nanometer range and their special chemical and physical behavior in the substrate. In this work, helium and neon ion beams from a helium ion microscope are compared with ion beams such as lithium, beryllium, boron, and silicon, obtained from a mass-separated FIB using a liquid metal alloy ion source (LMAIS) with respect to the imaging and milling resolution, as well as the current stability. Simulations were carried out to investigate whether the experimentally smallest ion-milled trenches are limited by the size of the collision cascade. While He+ offers, experimentally and in simulations, the smallest minimum trench width, light ion species such as Li+ or Be+ from a LMAIS offer higher milling rates and ion currents while outperforming the milling resolution of Ne+ from a gas field ion source. The comparison allows one to select the best possible ion species for the specific demands in terms of resolution, beam current, and volume to be drilled.

APA, Harvard, Vancouver, ISO, and other styles

31

Bauer, W., A. Brandelik, A. Citron, H. Ehrler, E. Halter, G. Melchior, K. Mittag, A. Rogner, and C. Schultheiss. "Pseudospark ion diodes." Laser and Particle Beams 5, no. 4 (November 1987): 581–87. http://dx.doi.org/10.1017/s026303460000313x.

Full text

Abstract:

The Pseudospark is an axially symmetric, high-voltage gas discharge operating at pressures below 100 Pa. It is capable of producing pinched high current ion beams. Streak camera photographs of the operation of this discharge reveal that a pinch with a diameter of ∼1 mm occurs in the diode. The beam then expands to about 1 to 10 mm in a distance of 12 cm. The beam-target interaction shows a UV-emitting plasma corresponding to protons with a main energy of 100 keV and a current density of about 16 kA/cm2. Initial theoretical results for the pseudospark are given.

APA, Harvard, Vancouver, ISO, and other styles

32

GRISHAM, L. R. "Potential roles for heavy negative ions as driver beams." Laser and Particle Beams 21, no. 4 (October 2003): 545–48. http://dx.doi.org/10.1017/s0263034603214117.

Full text

Abstract:

We have performed an initial assessment of the feasibility of producing heavy negative ion beams as drivers for an inertial confinement fusion reactor. Negative ion beams offer the potentially important advantages relative to positive ions that they will not draw electrons from surfaces and the target chamber plasma during acceleration, compression, and focusing, and they will not have a low energy tail. Intense negative ion beams could also be efficiently converted to atomically neutral beams by photodetachment prior to entering the target chamber. Depending on the target chamber pressure, this atomic beam will undergo ionization as it crosses the chamber, but at chamber pressures at least as high as 1.3 × 10−4 torr, there may still be significant improvements in the beam spot size on the target, due to the reduction in path-averaged self-field perveance. The halogens, with their large electron affinities, are the best negative ion candidates. Fluorine and chlorine are the easiest halogens to use for near-term source experiments, whereas bromine and iodine best meet present expectations of driver mass. With regard to ion sources and photodetachment neutralizers, this approach should be feasible with existing technology. Except for the target chamber, the vacuum requirements for accelerating and transporting high energy negative ions are essentially the same as for positive ions.

APA, Harvard, Vancouver, ISO, and other styles

33

Katayama, T., A. Itano, A. Noda, M. Takanaka, S. Yamada, and Y. Hirao. "Design study of a heavy ion fusion driver, HIBLIC." Laser and Particle Beams 3, no. 1 (February 1985): 9–27. http://dx.doi.org/10.1017/s0263034600001221.

Full text

Abstract:

A heavy ion fusion (HIF) system, named HIBLIC (Heavy Ion Beam and LIthium Curtain) is conceptually designed. The driver system consists of RF linacs (RFQ linacs, IH linacs and Alvarez linacs), storage rings (one accumulator ring and three buncher rings) and beam transport lines with induction beam compressors. This accelerator complex provides 6 beams of 15 GeV208Pb1+ ions to be focused simultaneously on a target. Each beam carries 1·78 kA current with 25 ns pulse duration, i.e., the total incident energy on the target is 4 MJ, 160 TW per shot. Superconducting coils are used in most parts of the magnet system to reduce power consumption.

APA, Harvard, Vancouver, ISO, and other styles

34

DEWALD, E., C. CONSTANTIN, S. UDREA, J. JACOBY, D. H. H. HOFFMANN, C. NIEMANN, J. WIESER, et al. "Studies of high energy density in matter driven by heavy ion beams in solid targets." Laser and Particle Beams 20, no. 3 (July 2002): 399–403. http://dx.doi.org/10.1017/s0263034602203055.

Full text

Abstract:

By the interaction of intense (1010 particles/500 ns) relativistic (∼300 MeV/amu) heavy ion beams with solid targets, large volumes (several cubic millimeters) of strongly coupled plasmas are produced at solid-state densities and temperatures of up to 1 eV, with relevance for equation-of-state (EOS) studies of matter at high energy density and heavy ion-beam-driven inertial confinement fusion (ICF). The time and space profile of the ion beams, focused by the plasma lens to diameters of a minimum of 0.5 mm in order to obtain specific energy depositions of up to about 4 kJ/g, were measured to calculate the energy deposition in the target. In the present work, the plasmas created by ion beam interaction with cryogenic gas crystals and metallic targets are studied, among other methods, by backlighting shadowgraphy and electrical conductivity measurements. The experiments are coupled with two-dimensional hydrodynamic simulations.

APA, Harvard, Vancouver, ISO, and other styles

35

Bock, R. "German heavy-ion ICF activities: Status and prospects." Laser and Particle Beams 8, no. 4 (December 1990): 563–73. http://dx.doi.org/10.1017/s0263034600008995.

Full text

Abstract:

The main goals of the German program are the study of key issues of inertial fusion with intense beams of heavy ions. The completion of the new heavy-ion synchrotron and storage ring facility SIS/ESR at GSI opens new directions for experimental investigations on beam dynamics at high intensity and on beam/target interaction. In addition, new accelerator scenarios will be investigated based on non-Liouvillean beam-handling techniques.

APA, Harvard, Vancouver, ISO, and other styles

36

Rubbia, Carlo. "Heavy-ion accelerators for inertial confinement fusion." Laser and Particle Beams 11, no. 2 (June 1993): 391–414. http://dx.doi.org/10.1017/s0263034600004985.

Full text

Abstract:

Two concepts have been applied to the classical problem of accelerators for the ignition of indirectly driven inertial fusion. The first is the use of non-Liouvillian stacking based on photoionisation of a singly charged ion beam. A special FEL appears the most suited device to generate the appropriate light beam intensity at the required wavelength. The second is based on the use of a large number of (>1000) beamlets–or “beam straws”–all focussed by an appropriate magnetic structure and concentrated on the same spot on the pellet. The use of a large number of beams–each with a relatively low-current density–elegantly circumvents the problems of space charge, making use of the non-Liouvillian nature of the stopping power of the material of the pellet. The present conceptual design is based on a low-current (〈i〉 ≈ 50 mA) heavy-ion beam accelerated with a standard LINAC structure and accumulated in a stack of rings with the help of photoionisation. Beams are then extracted simultaneously from all the rings and further subdivided with the help of a switchyard of alternate paths separating and synchronising the many bunches from each ring before they hit the pellet. Single beam straws carry a reasonable number of ions: Beams and technology are directly relatable to the ones presently employed, for instance, at the CERN-PS. Space-charge-dominated conditions arise only during the last few turns before extraction and in the beam transport channel to the reaction chamber. In a practical example, we aim at a peak power of 500 TW delivered to the pellet for a duration of 10–15 ns. High-energy (10 GeV) beam straws of Ba doubly ionised ions are concentrated on several (four) focal spots of a radius of about 1 mm. The power density deposited on these tiny cylindrical absorbers inside a hermetic “hohlraum” is about 2.5 × 1016 w/g. These conditions are believed to be optimal for X-ray conversion, i.e., with an estimated conversion efficiency of about 90%.

APA, Harvard, Vancouver, ISO, and other styles

37

Träbert, Elmar. "Extreme ultraviolet spectra of highly charged Fe ions in the laboratory versus the excitation of spectra in astrophysical environments." Canadian Journal of Physics 95, no. 9 (September 2017): 777–82. http://dx.doi.org/10.1139/cjp-2016-0623.

Full text

Abstract:

The ASOS meetings address atomic spectra and oscillator strengths for astrophysics and laboratory plasmas. Based on examples of Fe spectra from foil-excited ion beams and electron beam ion traps, some practical problems of laboratory studies using these tools in support of astrophysical observations are discussed.

APA, Harvard, Vancouver, ISO, and other styles

38

Wieser, J., A. Ulrich, B. Busch, R. Gernhäuser, W. Krötz, G. Ribitzki, M. Salvermoser, and D. E. Murnick. "Heavy-ion beam-pumped lasers: Optical gain on the 476.5-nm Ar II transition." Laser and Particle Beams 11, no. 3 (September 1993): 529–35. http://dx.doi.org/10.1017/s0263034600005188.

Full text

Abstract:

The possibility of heavy-ion beam-pumped ion lasers is demonstrated by observation of optical gain on the 476.5-nm Ar II 4p–4s ion laser transition in argon gas excited by 2.5–ns pulses of 110–MeV 32S ions with repetition rates up to 156 kHz. The particle energy per pulse was about 20 μJ. The projectiles were stopped in the target at pressures between 5 and 35 kPa. The beam from an argon ion probe laser operated at 476.5 nm was used to determine gain amplitude and time structure from a measured transient increase of the probe laser intensity when target excitation by the ion beam was present. The maximum gain observed was (0.5 ± 0.1) x 10-3 at a target gas pressure of 5 kPa. The optical gain observed in argon is consistent with calculations based upon an analysis of spectroscopic studies of rare gas targets excited by heavy-ion beams.

APA, Harvard, Vancouver, ISO, and other styles

39

WELCH, D. R., D. V. ROSE, W. M. SHARP, C. L. OLSON, and S. S. YU. "Effects of preneutralization on heavy ion fusion chamber transport." Laser and Particle Beams 20, no. 4 (October 2002): 621–25. http://dx.doi.org/10.1017/s0263034602204279.

Full text

Abstract:

Beams for heavy ion fusion are likely to require at least partial neutralization in the reactor chamber. Present target designs call for higher beam currents and smaller focal spots than most earlier designs, leading to high space-charge fields. Focusing is complicated by beam stripping in the low-pressure background gas expected in chambers. One method proposed for neutralization is passing an ion beam through a plasma before the beam enters the chamber. In this article, the electromagnetic particle-in-cell code LSP is used to study the effectiveness of this form of preneutralization for a range of plasma and beam parameters. For target chamber pressures below a few milliTorr of flibe gas, preneutralization is found to significantly reduce the beam emittance growth and spot size in the chamber.

APA, Harvard, Vancouver, ISO, and other styles

40

BRÄUNING, H., A. DIEHL, K. v. DIEMAR, A. THEIß, R. TRASSL, E. SALZBORN, and I. HOFMANN. "Charge-changing ion–ion collisions in heavy ion fusion." Laser and Particle Beams 20, no. 3 (July 2002): 493–95. http://dx.doi.org/10.1017/s0263034602203262.

Full text

Abstract:

In heavy ion fusion, the compression of the DT pellet requires high intensity beams of ions in the gigaelectron volt energy range. Charge-changing collisions due to intrabeam scattering can have a high impact on the design of adequate accelerator and storage rings. Not only do intensity losses have to be taken into account, but also the deposition of energy on the beam lines after bending magnets, for example, may be nonnegligible. The center-of-mass energy for these intrabeam collisions is typically in the kiloelectron volt range for beam energies in the order of several gigaelectron volts. In this article, we present experimental cross sections for charge transfer and ionization in homonuclear collisions of Ar4+, Kr4+, and Xe4+, and for charge transfer only in homonuclear collisions of Pb4+ and Bi4+. Using a hypothetical 100-Tm synchrotron as an example, expected particle losses are calculated based on the experimental data. The results are compared with expectations for singly charged Bi+ ions, which are usually considered for heavy ion fusion.

APA, Harvard, Vancouver, ISO, and other styles

41

Iwaki, Masaya. "Ion Beam Modification of Carbon Materials." Solid State Phenomena 107 (October 2005): 107–10. http://dx.doi.org/10.4028/www.scientific.net/ssp.107.107.

Full text

Abstract:

A study has been made of surface properties of carbon materials modified by ion beams. Substrates used were natural diamonds, glass-like carbon plates and polymer sheets. Ion species were chemically-active elements such as C, N and O, inert gas elements such as He, Ne and Ar, and metallic elements such as Cr and Ti. It was found that diamond becomes electrically conductive in ion implanted layers, which are amorphous or graphite-like structures. Electrical conductivity depends on implanted species, doses and target temperatures. It was found that glass-like carbon consisting of graphite and disordered graphite becomes amorphous due to ion beam bombardment. Amorphization causes the wear resistance to improve. The electrochemical properties changes depending on implanted species. The wear resistance and electrochemical properties depended on the target temperature during ion implantation. Ion beam bombardment to polymers has been carried out to control the electrical conductivity, cell adhesion and bio-compatibility. The electrical conductivity of polyimide films increases as the dose increases. The saturated sheet resistivity of implanted layers depends on ion species, dose and dose rate. It was found that the cell adhesion can be controlled by ion beam bombardment. The results were used in the fields of clinical examinations. In summary, ion beam bombardment to carbon materials is useful to control the carbon structures and surface properties depending on ion implantation conditions.

APA, Harvard, Vancouver, ISO, and other styles

42

Benkhelifa, El-Amine, and Mourad Djebli. "Plasma expansion dynamics in the presence of a relativistic electron beam." Laser and Particle Beams 33, no. 2 (March 19, 2015): 273–77. http://dx.doi.org/10.1017/s0263034615000166.

Full text

Abstract:

AbstractThe dynamics of an electron–ion plasma is studied when a mono-energetic relativistic electron beam penetrates the expanding plasma. Combined effects of thermal pressure and ambipolar electrostatic potential are considered for fully relativistic multi-fluids model where the quasi-neutrality assumption is used for a beam–plasma system. Relativistic effects are considered for both density and velocity of the beam fluid. Ion acceleration is depicted through a spike-like structure resulting from non-local charge separation and associated with the beak-down of quasi-neutrality. The beam initial speed is found to enhance the spike amplitude and change its position. Moreover, relativistic effects are particularly found significant for a non-thermal plasma.

APA, Harvard, Vancouver, ISO, and other styles

43

Kang, Xiangdong, Katsumi Masugata, and Kiyoshi Yatsui. "Evaluation of ablation plasma characteristics of intense, pulsed, ion-beam evaporation." Laser and Particle Beams 13, no. 2 (June 1995): 201–10. http://dx.doi.org/10.1017/s0263034600009320.

Full text

Abstract:

Basic characteristics of an ablation plasma produced by an intense, pulsed, ion beam have been evaluated from the measurement of ion-flux density by a biased ion collector. The target mass loss is detected by the measurement of the weight of the target in the comparison before and after the shot. A one-dimensional hydrodynamic model is introduced with the assumption of a high-power, light-ion beam-driven expansion and the following adiabatic expansion into vacuum. With this model, it is possible for us to deduce the temperature and the pressure from the data of the ion flux and the mass loss of the target, respectively. This method is also applicable to other intense pulsed energy sources such as lasers or electron beams.

APA, Harvard, Vancouver, ISO, and other styles

44

Yatsui, K., A. Tokuchi, H. Tanaka, H. Ishizuka, A. Kawai, E. Sai, K. Masugata, M. Ito, and M. Matsui. "Geometric focusing of intense pulsed ion beams from racetrack type magnetically insulated diodes." Laser and Particle Beams 3, no. 2 (May 1985): 119–55. http://dx.doi.org/10.1017/s026303460000135x.

Full text

Abstract:

Focusing properties and mechanisms are experimentally investigated of an intense pulsed light-ion beam or a medium-mass ion beam extracted from racetrack type magnetically insulated diodes. Quantitative determinations are made for three factors that affect the focusing ability of the beam, i.e., local divergence angle, deviation angle from ideal trajectory and space-charge effect. Behaviour of electrons in an anodecathode gap as well as neutralizing process of the ion beam by electrons are studied in connection with beam focusing. It is found that there is a close correlation between ion yield and electron irradiation on the anode. By adopting a perforated cathode instead of a vane cathode to ensure good uniformity of electric field in the accelerating gap, we have succeeded in significantly reducing the divergence angle. Several new diagnostic techniques and methods have been developed, yielding information such as the time-resolved trajectory and profile or incident angle of the beam. Electron temperature of the anode plasma is theoretically anticipated from the ions observed experimentally. From an estimate of beam divergence due to a space-charge effect, it is suggested that ‘breakeven’ can be achieved without using conventional z-discharged plasma channels if a bunch of boron beams is utilized.

APA, Harvard, Vancouver, ISO, and other styles

45

Ramirez, J. J., D. L. Cook, J. K. Rice, M. K. Matzen, D. L. Johnson, J. D. Boyes, C. L. Olson, et al. "Intense light-ion beams provide a robust, common-driver path toward ignition, gain, and commercial fusion energy." Laser and Particle Beams 11, no. 2 (June 1993): 423–30. http://dx.doi.org/10.1017/s0263034600005000.

Full text

Abstract:

Intense light-ion beams are being developed for investigations of inertial confinement fusion (ICF). This effort has concentrated on developing the Particle Beam Fusion Accelerator II (PBFA II) at Sandia as a driver for ICF target experiments, on design concepts for a high-yield, high-gain Laboratory Microfusion Facility (LMF), and on a comprehensive system study of a light-ion beam-driven commercial fusion reactor (LIBRA). This article reports on the status of design concepts and research in these areas.

APA, Harvard, Vancouver, ISO, and other styles

46

Bystritskii, V. M., A. V. Kharlov, G. A. Mesyats, A. V. Mytnikov, and A. A. Sinebrjukhov. "Experiments on generation of a high-power ion beam in a plasma-filled diode." Laser and Particle Beams 11, no. 1 (March 1993): 269–76. http://dx.doi.org/10.1017/s0263034600007102.

Full text

Abstract:

The experimental results on high-power ion beams (HPIB) generation in a plasma-filled, spherical-focusing diode with self-magnetic insulation that was placed for a load at nanosecond accelerator PARUS of 0.2-TW power and 60-ns pulse duration (in a matched load case) are given. The regimes of plasma-filled diode operation and generation of the ion beam were investigated. For optimal time delay between the plasma gun's pulse and accelerator firing, the stable operation in the plasma opening switch mode with a power enhancement factor of 2.3 and efficiency of ion beam generation of 20–25% was obtained. The maximal value of the ion current density reached in the focal plane was 15 kA/cm2.

APA, Harvard, Vancouver, ISO, and other styles

47

VARENTSOV, D., P. SPILLER, N. A. TAHIR, D. H. H. HOFFMANN, C. CONSTANTIN, E. DEWALD, J. JACOBY, et al. "Energy loss dynamics of intense heavy ion beams interacting with solid targets." Laser and Particle Beams 20, no. 3 (July 2002): 485–91. http://dx.doi.org/10.1017/s0263034602203250.

Full text

Abstract:

At the Gesellschaft für Schwerionenforschung (GSI, Darmstadt) intense beams of energetic heavy ions have been used to generate high-energy-density (HED) state in matter by impact on solid targets. Recently, we have developed a new method by which we use the same heavy ion beam that heats the target to provide information about the physical state of the interior of the target (Varentsov et al., 2001). This is accomplished by measuring the energy loss dynamics (ELD) of the beam emerging from the back surface of the target. For this purpose, a new time-resolving energy loss spectrometer (scintillating Bragg-peak (SBP) spectrometer) has been developed. In our experiments we have measured energy loss dynamics of intense beams of 238U, 86Kr, 40Ar, and 18O ions during the interaction with solid rare-gas targets, such as solid Ne and solid Xe. We observed continuous reduction in the energy loss during the interaction time due to rapid hydrodynamic response of the ion-beam-heated target matter. These are the first measurements of this kind. Two-dimensional hydrodynamic simulations were carried out using the beam and target parameters of the experiments. The conducted research has established that the ELD measurement technique is an excellent diagnostic method for HED matter. It specifically allows for direct and quantitative comparison with the results of hydrodynamic simulations, providing experimental data for verification of computer codes and underlying theoretical models. The ELD measurements will be used as a standard diagnostics in the future experiments on investigation of the HED matter induced by intense heavy ion beams, such as the HI-HEX (Heavy Ion Heating and EXpansion) EOS studies (Hoffmann et al., 2002).

APA, Harvard, Vancouver, ISO, and other styles

48

Ni, P. A., B. G. Logan, S. M. Lund, N. Alexander, F. M. Bieniosek, R. H. Cohen, M. Roth, and G. Schaumann. "Feasibility study of the magnetic beam self-focusing phenomenon in a stack of conducting foils: Application to TNSA proton beams." Laser and Particle Beams 31, no. 1 (December 18, 2012): 81–88. http://dx.doi.org/10.1017/s0263034612001000.

Full text

Abstract:

AbstractThis paper investigates prospects of utilizing a high-power laser-driven target-normal-sheath-acceleration proton beam for the experimental demonstration of the magnetic self-focusing phenomenon in charged particle beams. In the proposed concept, focusing is achieved by propagating a space-charge dominated ion beam through a stack of thin conducting and grounded foils separated by vacuum gaps. As the beam travels through the system, image charges build up at the foils and generate electric field that counteracts the beam's electrostatic self-field — a dominant force responsible for expansion of a high current beam. Once the electrostatic self-field is “neutralized” by the image charges, the beam currents magnetic self-field will do the focusing. The focal spot size and focal length depends on the choice of a number of foils and distance between foils. Considering the typical electrical current level of a target-normal-sheath-acceleration proton beam, we conclude that it is feasible to focus or collimate a beam within tens of millimeters distance, e.g., using 200–1000 Al foils, 0.5 µm thick each, with foil spacing ranging from 25 µm to 100 µm. These requirements are within technical capabilities of modern target fabrication, thus allowing the first possible demonstration of the pinch effect with heavy ion beams.

APA, Harvard, Vancouver, ISO, and other styles

49

Zhu, X. P., L. Ding, Q. Zhang, Yu Isakova, Y. Bondarenko, A. I. Pushkarev, and M. K. Lei. "Generation and transportation of high-intensity pulsed ion beam at varying background pressures." Laser and Particle Beams 35, no. 4 (September 13, 2017): 587–96. http://dx.doi.org/10.1017/s026303461700060x.

Full text

Abstract:

AbstractHigh-intensity pulsed ion beam (HIPIB) technology is developed as an advanced manufacturing method for components with improved wear, corrosion and/or fatigue performance, etc. Robust HIPIB equipment with stable repetitive operation, long-lifetime, and easy maintenance are desired for industrial applications, on which stability of ion beam parameters is critical to achieve consistent result of reproducibility. Here, magnetically insulated ion diodes (MIDs) as ion source with durable graphite anode are investigated in a simple self-magnetic field configuration under repetitive operation. Influence of background pressure on ion beam generation and transportation is emphasized since ion beam sources were intrinsically a vacuum-based system. Comparative experiments were conducted on two types of HIPIB equipment, that is, TEMP-6 and TEMP-4M, differing in vacuum packages where turbo-molecular pump or oil diffusion pump was used. Both the HIPIB equipments are operated on a bipolar pulse mode, that is, a first negative pulse of 150–200 kV with pulse duration 450–500 ns to generate anode plasma on explosive electron emission, and a second positive pulse of 200–250 kV with 120 ns to accelerate the ions. Ion beam energy density up to 8 J/cm2 is achievable using MIDs of geometrical focusing configuration, and the total energy, energy density distribution along cross-section, deflection and divergence, and charge neutralization of the ion beams are assessed under background pressures in a wide range of two orders of magnitude, that is, 1–100 mPa. No appreciable change in the parameters is observed up to 50 mPa, and merely a slight increase in the beam deflection from about ±3 mm to about ±4 mm at the focal point over 50 mPa. The stability of ion beam at the varied pressure is mainly facilitated by the higher pressure up to several Pa in anode–cathode gap during plasma generation and good neutralizing effect for ion beam transportation.

APA, Harvard, Vancouver, ISO, and other styles

50

Wei, J., H. Ao, S. Beher, N. Bultman, F. Casagrande, S. Cogan, C. Compton, et al. "Advances of the FRIB project." International Journal of Modern Physics E 28, no. 03 (March 2019): 1930003. http://dx.doi.org/10.1142/s0218301319300030.

Full text

Abstract:

The Facility for Rare Isotope Beams (FRIB) Project has entered the phase of beam commissioning starting from the room-temperature front end and the superconducting linac segment of first 15 cryomodules. With the newly commissioned helium refrigeration system supplying 4.5[Formula: see text]K liquid helium to the quarter-wave resonators and solenoids, the FRIB accelerator team achieved the sectional key performance parameters as designed ahead of schedule accelerating heavy ion beams above 20[Formula: see text]MeV/u energy. Thus, FRIB accelerator becomes world’s highest-energy heavy ion linear accelerator. We also validated machine protection and personnel protection systems that will be crucial to the next phase of commissioning. FRIB is on track towards a national user facility at the power frontier with a beam power two orders of magnitude higher than operating heavy-ion facilities. This paper summarizes the status of accelerator design, technology development, construction, commissioning as well as path to operations and upgrades.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Ion Beam Physik'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles