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《Comptes Rendus de l''Academie des Sciences Series IV Physics》2000,1(6):751-758
The basic physics of heavy-ion driven inertial fusion is timely reviewed. Emphasis is laid on the effects of strong space charge. 相似文献
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Mehlhorn T.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(6):1336-1356
Intense beams of light and heavy ions are being studied as inertial confinement fusion (ICF) drivers for high yield and energy. Heavy and light ions have common interests in beam transport, targets, and alternative accelerators. Self-pinched transport is being jointly studied. This article reviews the development of intense ion beams for ICF. Light-ion drivers are highlighted because they are compact, modular, efficient and low cost. Issues facing light ions are: (1) decreasing beam divergence; (2) increasing beam brightness; and (3) demonstrating self-pinched transport. Applied-B ion diodes are favored because of efficiency, beam brightness, perceived scalability, achievable focal intensity, and multistage capability. A light-ion concept addressing these issues uses: (1) an injector divergence of ⩽24 mrad at 9 MeV; (2) two-stage acceleration to reduce divergence to ⩽12 mrad at 35 MeV; and (3) self-pinched transport accepting divergences up to 12 mrad. Substantial progress in ion-driven target physics and repetitive ion diode technology is also presented. Z-pinch drivers are being pursued as the shortest pulsed power path to target physics experiments and high-yield fusion. However, light ions remain the pulsed power ICF driver of choice for high-yield fusion energy applications that require driver standoff and repetitive operation 相似文献
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A. Lorusso M. V. Siciliano L. Velardi V. Nassisi 《Applied Physics A: Materials Science & Processing》2010,101(1):179-183
We developed an ion accelerator with a double accelerating gap system supplied by two power generators of different polarity.
The ions were generated by laser ion source technique. The laser plasma induced by an excimer KrF laser, freely expanded before
the action of accelerating fields. After the first gap action, the ions were again accelerated by a second gap. The total
acceleration can imprint a maximum ion energy up to 160 keV per charge state. We analysed the extracted charge from a Cu target
as a function of the accelerating voltage at laser energy of 9, 11 and 17 mJ deposited on a spot of 0.005 cm2. The peak of current density was 3.9 and 5.3 mA for the lower and medium laser energy at 60 kV. At the highest laser energy,
the maximum output current was 11.7 mA with an accelerating voltage of 50 kV. The maximum ion dose was estimated to be 1012 ions/cm2. Under the condition of 60 kV accelerating voltage and 5.3 mA output current the normalized emittance of the beam measured
by pepper pot method was 0.22 π mm mrad. 相似文献
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A series of carbon-coated magnetic recording disks proved ideal for exploring sampling depth and ion formation trends as a function of variations in energy and cluster size (Aux) of the primary ion beam, and variations in over coat thickness and type. Ion yield from the underlying metal layer increased with increasing energy and decreasing cluster size of the primary ions. The yields varied nearly linearly with over layer thickness. In contrast, MxCsy depth profiles were unaffected by changes in the primary ion. The samples were fortuitously dosed with dinonyl phthalate, allowing a study similar to prior GSIMS work [I.S. Gilmore, M.P. Seah, J.E. Johnstone, in: A. Benninghoven, P. Bertrand, H.-N. Migeon, H.W. Werner (Eds.), Proceedings of the 12th International Conference on SIMS, Elsevier, Brussels, 2000, p. 801]. Ions prominent in the EI mass spectrum, including even electron ions, were more consistently enhanced at lower energies and higher cluster sizes than the primary (M + H)+ ion. The total secondary ion count was inversely proportional to the film thickness. Secondary electrons, largely originating in the buried metal layer, may be inducing organic ion formation [A.M. Spool, Surf. Interface Anal. 36 (2004) 264]. 相似文献
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D.P. Barber U. Becker H. Benda A. Böhm J.G. Branson J. Bron D. Buikman J.D. Burger C.C. Chang H.S. Chen M. Chen C.P. Cheng Y.S. Chu R. Clare P. Duinker G.Y. Fang H. Fesefeldt R.Y. Zhu 《Physics Reports》1980,63(7):337-340
This report reviews the experimental investigation of high energy e+e? interactions by the MARK J collaboration at PETRA, the electron-positron colliding beam accelerator at DESY in Hamburg, Germany. The physics objectives include studies of several purely electromagnetic processes and hadronic final states, which further our knowledge of the nature of the fundamental constituents and of their strong, electromagnetic and weak interactions. Before discussing the physics results, the main features and the principal components of the MARK J detector are discussed in terms of design, function, and performance. Several aspects of the on-line data collection and the off-line analysis are also outlined. Results are presented on tests of quantum electrodynamics using e+e? → e+e?, μ+μ? and τ+τ?, on the measurement of R, the ratio of the hadronic to the point-like muon pair cross section, on the search for new quark flavors, on the discovery of three jet events arising from the radiation of hard noncollinear gluons as predicted by quantum chromodynamics, and on the determination of the strong coupling constant αs. 相似文献
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I.G. Bearden H. Bøggild J. Boissevain P.H.L. Christiansen L. Conin J. Dodd B. Erazmus S. Esumi C.W. Fabjan D. Ferenc A. Franz J.J. Gaardhøje A.G. Hansen O. Hansen D. Hardtke H. van Hecke E.B. Holzer T.J. Humanic P. Hummel B.V. Jacak K. Kaimi M. Kaneta T. Kohama M. Kopytine M. Leltchouk A. Ljubičić Jr. B. Lörstad L. Martin A. Medvedev M. Murray H. Ohnishi G. Paić S.U. Pandey F. Piuz J. Pluta V. Polychronakos M. Potekhin G. Poulard D. Reichhold A. Sakaguchi J. Schmidt-Sørensen J. Simon-Gillo W. Sondheim T. Sugitate J.P. Sullivan Y. Sumi W.J. Willis K. Wolf N. Xu D.S. Zachary 《The European Physical Journal C - Particles and Fields》2002,23(2):237-247
Proton and deuteron production has been observed in S+S and S+Pb collisions at 200 AGeV and in Pb+Pb reactions at 158 AGeV at the CERN SPS accelerator. For Pb+Pb triton production was also measured. The p and d spectra as well as the p and t
spectra were observed in similar rapidity ranges and over similar ranges of transverse momenta per nucleon, making it possible
to interpret the cross sections of the composite particles in terms of coalescence mechanisms. Volumes of homogeneity were
extracted and compared to pion-pair HBT interferometry results. Special attention is given to the dependence on transverse
mass, centrality and rapidity.
Received: 23 July 2001 / Revised version: 16 November 2001 / Published online: 25 January 2002 相似文献
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R. Peretz 《Optics and Lasers in Engineering》1989,10(1)
As a result of the unification of two models previously described by the author, a three-dimensional treatment of the workpiece temperature distribution, which takes into consideration the solid to liquid phase change of the processed material, is presented for deep penetration welding (d.p.w.) with high energy focused beans.The new model improves the accuracy of weld geometry prediction by better correlating the shape, width and depth of the cross-section of the resolidified weld with beam characteristics, material thermophysical properties, workpiece velocity and preheating temperature. 相似文献
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A solution for the two-dimensional temperature field in a workpiece at welding by laser or electron beams, which takes into consideration the solid-to-liquid phase change of the material, is presented. This leads to more precise process parameter correlations. 相似文献
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J. Gierak D. Mailly P. Hawkes R. Jede L. Bruchhaus L. Bardotti B. Prével P. Mélinon A. Perez R. Hyndman J.-P. Jamet J. Ferré A. Mougin C. Chappert V. Mathet P. Warin J. Chapman 《Applied Physics A: Materials Science & Processing》2005,80(1):187-194
Controlled and reproducible fabrication of nano-structured materials will be one of the main industrial challenges in the next few years. We have recently proposed exploitation of the nano-structuring potential of a high resolution Focused Ion Beam Tool, to overcome basic limitations of current nano-fabrication techniques. The aim of this article is to present some new routes for material patterning, which benefit from ion-induced local property modifications or damage. In the experiments we describe hereafter an ultra-sharp pencil of 30 keV gallium ions is used to tailor the characteristics of several materials at a scale of a few nanometres. The experimental results are then compared to simulations. First, we simulate the control of collisional defects generated in a thin magnetic layer under FIB irradiation. The results explain the stable magnetic structures we have obtained experimentally. This was achieved with a low surface ion dose (1012 to 1014 ions/cm2). In addition we have explored the promising direction of Bottom-up or self-organization processes using a FIB instrument. We have defined artificial surface defects. These defects created by the impact of an 8-nm FWHM probe were used to pin the diffusion and to organize nanometre-sized gold clusters on a graphite surface. PACS 79.20.Rf; 81.07.-b 相似文献
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D. Dinev 《Physics of Particles and Nuclei》2009,40(2):257-277
A review of processes that occur in high energy heavy ion acceleration by synchrotrons and colliders and that are essential
for the accelerator performance is presented. Interactions of ions with the residual gas molecules/atoms and with stripping
foils that deliberately intercept the ion trajectories are described in details. These interactions limit both the beam intensity
and the beam quality. The processes of electron loss and capture lie at the root of heavy ion charge exchange injection. The
review pays special attention to the ion induced vacuum pressure instability which is one of the main factors limiting the
beam intensity. The intrabeam scattering phenomena which restricts the average luminosity of ion colliders is discussed. Some
processes in nuclear interactions of ultra-relativistic heavy ions that could be dangerous for the performance of ion colliders
are represented in the last chapter.
The text was submitted by the author in English. 相似文献
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给出用“闪光二号”加速器高功率离子束轰击19F靶产生6~7MeV准单能脉冲γ射线的实验结果;提出采用离子束传输法分离和降低轫致辐射干扰的方法,利用闪烁体探测器和半导体探测器,测出质子传输不同距离后轰击C2F4靶产生的6~7MeV准单能脉冲γ射线信号以及相比轫致辐射的延迟时间;介绍了模拟材料的软X射线的热 力学效应等方面的高功率离子束的应用,给出一些实验和理论计算结果。 相似文献
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H. Haas 《Hyperfine Interactions》1994,84(1):69-81
Nuclear methods using radiation detection are very well suited for surface and interface investigations, since they generally require only a small number of radioactive probe nuclei. Virtually isolated probe atoms can be investigated. The use of an isotope separator to solve the central problem in the application of radioactive atoms for the study of surfaces, the clean deposition of the probe nuclei, is described. First physics experiments include studies of desorption isochrones and characterization of adatom sites on flat and vicinal surfaces by PAC. A particularly complete picture could be obtained for Cd and In on the Pd(111) surface, where five different sites successively populated in the surface diffusion process were observed. Other nuclear methods suitable for a future extension of the surface investigations, such as Mössbauer spectroscopy, decay recoil angular distribution and emission channeling, are briefly discussed. 相似文献