| Paper | Title | Page |
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| TUPLT111 | RF Focusing of Low-Charge-to-Mass-Ratio Heavy-Ions in a Superconducting Linac | 1405 |
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| A post-accelerator of radioactive ions (RIB linac) must produce high-quality beams over the full mass range, including uranium, with high transmission and efficiency (P.N. Ostroumov and et al., Proc. of the PAC2001, p. 4080.). The initial section of the RIB linac is a low-charge-to-mass-ratio superconducting RF linac which will accelerate any ion with q/A>=1/66 to ~900 keV/u or higher. This section of the linac consists of many interdigital cavities operating at –20 degree synchronous phase and focusing can be provided by SC solenoids following each cavity. For the charge-to-mass ratio q/A=1/66 a proper focusing can be reached with the help of strong SC solenoid lenses with magnetic fields up to 15 T. These state-of-the-art solenoids are expensive. A possible lower cost alternative focusing method based on the combination of low-field SC solenoids and RF focusing is proposed and discussed in this paper. | ||
| TUPLT147 | Multiple-charge-state Beam Steering in High-intensity Heavy-ion Linacs | 1476 |
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An algorithm suitable for correction to steering of multiple-charge-state beams in heavy-ion linacs operating at high currents has been developed [*]. It follows a four-dimensional minimization procedure that includes coupling of the transverse beam motions. A major requirement is that it obeys the restricted lattice design imposed by the acceleration of multiple-charge-state heavy-ion beams [**]. We study the algorithm efficiency in controlling the beam effective emittance growth in the presence of random misalignments of cavities and focusing elements. Limits on misalignments are determined by quantifying beam losses and effective steering requirements are selected by examining several correcting schemes within the real-state constraints. The algorithm is used to perform statistically significant simulations to study beam losses under realistic steering.
* E. S. Lessner and P. N. Ostroumov, Proc. Part. Accel. Conf. (2003)** P. N. Ostroumov, Phys. Rev. STAB Vol. 5, 0030101 (2002) |
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| WEPLT145 | Beam Loss Studies in High-intensity Heavy-ion Linacs | 2173 |
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A low beam-loss budget is an essential requirement for high-intensity machines and represents one of their major design challenges. In a high-intensity heavy-ion machine, losses are required to be below 1 W/m for hands-on-maintenance. The driver linac of the Rare Isotope Accelerator (RIA) is designed to accelerate beams of any ion to energies from 400 MeV per nucleon for uranium up to 950 MeV for protons with a beam power of up to 400 kW. The high intensity of the heaviest ions is achieved by acceleration of multiple-charge-state beams, which requires a careful beam dynamics optimization to minimize effective emittance growth and beam halo formation. For beam loss simulation purposes, large number of particles must be tracked through the linac. Therefore the computer code TRACK [P.N. Ostroumov and K.W. Shepard, PRST AB 11, 030101 (2001)] has been parallelized and calculations is being performed on the JAZZ cluster [*] recently inaugurated at ANL. This paper discusses how this powerful tool is being used for simulations for the RIA project to help decide on the high-performance and cost-effective design of the driver linac.
* The Jazz Cluster, http://www.lcrc.anl.gov/jazz |
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| MOPLT153 | Electron-Ion Collider at CEBAF: New Insights and Conceptual Progress | 893 |
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| We report on progress in conceptual development of the proposed high luminosity (up to 1035/cm2s) and efficient spin manipulation (using figure 8 boosters and collider rings) Electron-Ion Collider at CEBAF based on use of polarized 5-7 GeV electrons in superconduction energy recovering linac (ERL with circulator ring, kicker-operated) and 30-150 GeV ion storage ring (polarized p, d. He3, Li and unpolarized nuclei up to Ar, all totally stripped). Ultra-high luminosity is envisioned to be achievable with short ion bunches and crab-crossing at 1.5 GHz bunch collision rate interaction points. Our recent studies concentrated on simulation of beam-beam interaction, preventing the electron cloud instability, calculating luminosity lifetime due to Touschek effect in ion beam and background scattering of ions, experiments on energy recovery at CEBAF, and other. These studies have been incorporated in the development of the luminosity calculator and in formulating minimum requirements to the polarized electron and ion sources |