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The 3-D particle-in-cell simulations with the code MANDOR demonstrate effective ion acceleration from the interaction of intense ultrashort linearly polarized laser pulses with both ultrathin solid dense foils and low-density targ...
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The 3-D particle-in-cell simulations with the code MANDOR demonstrate effective ion acceleration from the interaction of intense ultrashort linearly polarized laser pulses with both ultrathin solid dense foils and low-density targets when the laser energy ranges from several millijoules to tens of joules. The optimum foil thickness and the corresponding maximum energy of the accelerated ions for a given energy of the laser pulse were found. Different mechanisms of ion acceleration, such as target normal sheath acceleration, directed Coulomb explosion, and ponderomotive acceleration, are involved. We discuss the transition from one acceleration regime to another when the target thickness and density and the laser pulse intensity change and show that reducing the target density significantly increases the ion energy. We present some examples of isotope production as a possible application of multimegaelectronvolt proton beams on the joule scale of a laser.
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A DESIGN refinement in particle accelerators whereby the ion beam energy can be stepped up as much as four times to increase the utility of such machines in basic nuclear research was described recently by Dr. R. J. Van de Graaff,...
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A DESIGN refinement in particle accelerators whereby the ion beam energy can be stepped up as much as four times to increase the utility of such machines in basic nuclear research was described recently by Dr. R. J. Van de Graaff, Massachusetts Institute of Technology.
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A scheme to achieve all-optical cascaded ion acceleration driven by intense laser pulses is proposed, where a series of segmented tubes are used. First, the high-flux ion beam is produced via collisionless shock acceleration in th...
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A scheme to achieve all-optical cascaded ion acceleration driven by intense laser pulses is proposed, where a series of segmented tubes are used. First, the high-flux ion beam is produced via collisionless shock acceleration in the first tube segment driven by an intense picosecond laser, and then undergoes successive post-accelerations in a cascaded manner via magnetic vortex acceleration driven by low-power terawatt-femtosecond lasers when it propagates through each subsequent tube segment into the vacuum gaps between them. By controlling the delay of the femtosecond lasers as well as the vacuum gap between the tube segments, not only the maximum energy of the ion beam can be boosted, but also its energy spectrum can be tuned to be quasi-monoenergetic. Two-dimensional particle-in-cell simulations show that the maximum energy of the primary proton beam, produced by the picosecond laser at intensity 8.8 x 10(19) W cm(-2), can be boosted from 123 to 181 MeV with only two post-accelerations by using 100 fs lasers at the same intensities.
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To produce a compact and efficient particle accelerator, several different piezoelectric transformer configurations are evaluated for their applicability in this demanding application area. Using a derived 1-D model for three diff...
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To produce a compact and efficient particle accelerator, several different piezoelectric transformer configurations are evaluated for their applicability in this demanding application area. Using a derived 1-D model for three different electroding and mounting schemes, accelerator efficiency and gradient are optimized. It is shown that with some advancements in material yield strength and advanced bonding techniques, reaching 4 MeV/m with over 40% efficiency is possible.
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The KEK digital accelerator (DA) is an alternative to high-voltage electrostatic accelerators and conventional cyclotrons and synchrotrons, which are commonly used as swift heavy ion beam drivers. Compared with conventional accele...
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The KEK digital accelerator (DA) is an alternative to high-voltage electrostatic accelerators and conventional cyclotrons and synchrotrons, which are commonly used as swift heavy ion beam drivers. Compared with conventional accelerators, KEK-DA is capable of delivering a wider variety of ion species with various energies, as a result of its intrinsic properties. It is expected to serve as a heavy ion beam factory for research in materials science. Plans for its utilization include unique application programs, such as laboratory-based space science using virtual cosmic rays, heavy-ion mutagenesis in microorganisms, deep ion implantation, and modification of materials, which may be categorized into systematic studies of the spatial and temporal evolution of the locally and highly excited states of materials.
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The results of a 3D optimization study of ion acceleration from ultrathin solid density foils (Brantov et al 2015 Phys. Rev. Spec. Top. Accel. Beams 18 021301) are complemented with an improved analytic model of the directed Coulo...
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The results of a 3D optimization study of ion acceleration from ultrathin solid density foils (Brantov et al 2015 Phys. Rev. Spec. Top. Accel. Beams 18 021301) are complemented with an improved analytic model of the directed Coulomb explosion. Similarly to optimizing overdense targets, we also optimize low-density targets to obtain maximum ion energy, motivated by progress in producing a new generation of low-density slab targets whose density can be very homogeneous and as low as the relativistic critical density. Using 3D simulations, we show that for the same laser pulse, the ion energy can be significantly increased with low-density targets. A new acceleration mechanism is responsible for such an increase. This mechanism is described qualitatively, and it explains an advantage of low-density targets for high-energy ion production by lasers.
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The talks presented within WG2 confirmed the high level of activity in the field, displayed a significant progress in the understanding of the ion acceleration mechanisms, and highlighted important technological innovation. While ...
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The talks presented within WG2 confirmed the high level of activity in the field, displayed a significant progress in the understanding of the ion acceleration mechanisms, and highlighted important technological innovation. While there is still scope for optimising TNSA sources by applying advanced targetry concepts, and for developing innovative applications, acceleration dominantly due to radiation pressure or reflection from collisionless shocks, or enhanced by relativistic transparency effects can now be accessed by selecting particular interaction conditions and target parameters. This level of control and understanding is highly promising in view of further development with upcoming, next generation laser sources, providing higher laser power and/or repetition rate.
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In Flerov’s Laboratory of Nuclear Reactions of JINR in the framework of project “Beta” a cyclo-tron complex for a wide range of applied research in nanotechnology (track membranes, surface modifica-tion, etc.) is created. The c...
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In Flerov’s Laboratory of Nuclear Reactions of JINR in the framework of project “Beta” a cyclo-tron complex for a wide range of applied research in nanotechnology (track membranes, surface modifica-tion, etc.) is created. The complex includes a dedicated heavy-ion cyclotron DC-110, which yields intense beams of accelerated ions Ar, Kr and Xe with a fixed energy of 2.5 MeV/A. The cyclotron is equipped with external injection on the base of ECR ion source, a spiral inflector and the system of ions extraction consisting of an electrostatic deflector and a passive magnetic channel. The results of calculations of the beam dynamics in measured magnetic field from the exit of spiral inflector to correcting magnet located outside the acceler-ator vacuum chamber are presented. It is shown that the design parameters of ion beams at the entrance of correcting magnet will be obtained using false channel, which is a copy of the passive channel, located on the opposite side of the magnetic system. Extraction efficiency of ions will reach 75%.
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