| Paper | Title | Page |
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| MOPCH100 | Polarized Proton Acceleration in the AGS with Two Helical Partial Snakes | 273 |
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| Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and it is not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes with double pitch design have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results. The effect of horizontal intrinsic resonances in the presence of two partial snakes are also discussed. | ||
| TUPLS093 | AG Acceleration using DPIS | 1720 |
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| We are investigating high current and high repetition rate ion production methods for various heavy ions which can be utilized for an injector of an FFAG accelerator. Direct Plasma Injection Scheme (DPIS) is one of the candidates of the ion production methods and to confirm the capability of the DPIS, we are now preparing for accelerating high intensity Ag15+ ions. The DPIS uses a combination of Laser Ion Source (LIS) and RFQ linac. The plasma goes into the linac directly without transportation line and the ions are extracted at RFQ entrance. To determine the specifications of new RFQ electrodes, the plasma properties were measured. With the Nd-glass laser (3 J / 30 ns), we could not obtain high charge state ions. A new Nd-YAG laser (2.3 J / 6 ns) enabled us to observe many high charged ions and the most produced ions were Ag15+. We completed the plasma distribution measurements. Based on these results, we designed the new RFQ, which will accommodate Q / M = 1 / 8 particles, supposing Ag+15. | ||
| TUPLS095 | Recent Progress about DPIS | 0 |
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| We have focused on high brightness of induced plasma in Laser Ion Source (LIS) to provide intense highly charged ions efficiently. To take the advantage of the intrinsic density of the laser plasma, Direct Plasma Injection Scheme (DPIS) has been developed. The induced laser plasma has initial expanding velocity and can be delivered directly to the RFQ. Extraction electrodes and focusing devices in LEBT are not needed. Since 2004, a newly designed RFQ has been used to verify the capability of the new ion production scheme. We succeeded to accelerate 60 m A of Carbon beam and 60 mA of Aluminium beam. We have also tried to understand plasma properties of various species by measuring charge states distributions and time structures, and are now ready to accelerate heavier species. Currently Silver 15+ beam is planned to be accelerated. In the conference, design strategies and detailed techniques for the DPIS will be described based on the measured plasma properties of various elements and new findings obtained from recent acceleration experiments. The durability and the reproducibility will be also explained. | ||
| TUPLS097 | Application of DPIS to IH Linac | 1729 |
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| We are now designing a Laser Ion Source (LIS), which will be operated with an Inter-digital H (IH) structure linac using the Direct Plasma Injection Scheme (DPIS). The DPIS has been applied to RFQ linacs and has successfully achieved very high current with simple structure. The IH structure linac was designed to accept 40 keV proton beam which could be produced by the DPIS. The combination of the DPIS and IH structure linac will realize quite compact accelerator complex with intense proton beam. The detailed design study of a plasma production chamber with a cryogenic cooler is investigated. | ||
| TUPLS100 | Generation of Highly Charged Ions Using ND-glass Laser | 1735 |
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The parameters of ions (charge state distributions, currents and pulse durations) were measured in laser plasma generated by 3 J/30 ns Nd-glass laser for wide range of elements from 12C to 181Ta and for different laser power densities at the target surface. It is shown that such a laser can effectively generate highly charged ions for elements from 12C to 56Fe. Registered ion charge states significantly drops for heavier elements because of recombination losses of highly charged ions during laser produced plasma expansion into vacuum. Absolute currents and numbers of ions with different charge states were obtained by normalization of charge state distributions summary on total ion currents measured by Faraday cup for 1011 W/cm2 and 1012 W/cm2 laser power densities at the target surface. The results obtained are very useful for Laser Ion Source (LIS) development, in particular, for Direct Plasma Injection Scheme (DPIS) study*.
*M. Okamura et al. Laser and Particle Beams, 20, 2002, pp. 451 - 454. |