| Paper | Title | Page |
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| TUP039 | Two-Charge-State Injector for a High Power Heavy-Ion Linac* | 336 |
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A permanent magnet (PM) ECR ion source and following low energy beam transport (LEBT) system with the capability to deliver two-charge-state heavy-ion beams (2Q-LEBT) for high-power linacs is being prototyped at Argonne. The injector consists of the PM ECR ion source, transport line with beam diagnostics including emittance measurements and a multi-harmonic buncher. Recently the ECR ion source has been installed on a high voltage platform to increase the accelerating voltage up to the design value of 100 kV. The unique feature of the 2Q-LEBT layout is that the charge separation is performed off of the platform after acceleration of a multi-component ion beam. This layout allows us to analyze and recombine two-charge-state beams using an achromatic bending system. Improvements of the PM ECR performance and beam optics studies based on measurements of various heavy-ion beams will be discussed in this paper.
*This work was supported by the U. S. Department of Energy, Office of Nuclear Physics, under Contract No. W-31-109-ENG-38 |
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| TUP072 | Beam Dynamics Studies of the 8-GeV Superconducting H- Linac | 420 |
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A 8-GeV H-minus linac has been proposed to enhance the accelerator complex at Fermilab as a high-intensity neutrino source.* The linac is based on 430 independently phased superconducting cavities. The front-end of the linac (up to 420 MeV) operating at 325 MHz is based on RIA-type multi-spoke cavities. The rest of the linac (from 420 MeV to 8 GeV) uses ILC-type elliptical cavities. We have performed large scale end-to-end beam dynamics simulations of the driver linac using the code TRACK** including all sources of machine errors and detailed beam loss analysis. The results of these simulations will be presented and discussed.
* G. W. Foster and J. A. MacLachlan, Proceedings of LINAC-2002, p.826. |
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| TUP075 | Automatic Transverse and Longitudinal Tuning of Single and Multiple Charge State Ion Beams | 429 |
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Extensive end-to-end beam dynamics simulations of the RIA driver linac using the code TRACK and including all sources of machine errors and detailed beam loss analysis* showed that the losses could be significantly reduced for a fine-tuned linac. For this purpose we have developed an automatic longitudinal tuning proceedure for multiple charge state heavy-ion beams.** For a complete tuning tool, we have recently developed an automatic transverse tuning proceedure to produce smooth transverse beam dynamics by minimizing the RMS beam sizes after each focusing period. We have also extended the automatic longitudinal proceedure to produce smooth longitudinal beam dynamics for single and multiple charge state ion beams. In addition to improving an existing tune, this powerful automatic beam tuning tool can be used to retune the linac and restore the beam after one or more elements failures and to develop new tunes for ion beams with different Q/A ratios. After presenting the method, the results from some applications will be presented and discussed.
* P. Ostroumov, V. Assev and B. Mustapha, Phys. Rev. ST-AB 7 (2004) 090101 |
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| TUP076 | First TRACK Simulations of the SNS Linac | 432 |
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In an effort to benchmark the code TRACK* against the recent commissionnig data from the SNS linac, we started updating the code TRACK to support SNS-type elements like DTL's and CCL's. 2D electric field tables were computed using SUPERFISH and 3D magnetic fields from PMQ's were calculated using EMS-Studio. A special DTL routine was implemented and successfully tested. The first results of TRACK simulations using a realistic beam will be presented. A comparison with the code PARMILA will also be presented and discussed.
* "TRACK: The New Beam Dynamics code", V. N. Aseev et al, in Proceedings |
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| TUP079 | RIAPMTQ/IMPACT: Beam-Dynamics Simulation Tool for RIA | 441 |
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| We describe a multiple-charge-state simulation-code package for end-to-end computer simulations of the RIA heavy-ion driver linac, extending from the low-energy beam transport after the ECR source to the end of the linac. The work is being performed by a collaboration including LANL, LBNL, ANL, and MSU. The package consists of two codes, the code RIAPMTQ for the linac front end including the LEBT, RFQ, and MEBT, and the code IMPACT for the superconducting linac. This code package has been benchmarked for rms beam properties against previously existing codes at ANL and MSU. The simulation tool will allow high-statistics runs on parallel supercomputing platforms, such as NERSC, as well as runs on desktop PC computers for low-statistics design work. It will address an important near-term need for the RIA project, allowing evaluations of candidate designs with respect to beam-dynamics performance including beam losses, which can be compared with predictions of other existing simulation codes. | ||
| THP079 | High-Power Test of a 57-MHz CW RFQ | 767 |
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High power heavy-ion drivers require a CW low-frequency RFQ for initial acceleration. The technique of high-temperature furnace brazed OFE copper cavities has proven to be very reliable for the production of high-quality CW accelerating structures. By appropriate choice of the resonant structure for the RIA driver RFQ we have achieved moderate transverse dimensions of the cavity and high quality accelerating-focusing fields required for simultaneous acceleration of multiple charge state ion beams. In our application the RFQ must provide stable operation over a wide range of RF power levels. To demonstrate the technology and high-power operation we have built an engineering prototype of one-segment of the 57-MHz RFQ structure [1]. The RFQ is designed as a 100% OFE copper structure and fabricated with a two-step furnace brazing process. The brazing process was successful and the cavity was shown to be vacuum tight. The errors in the tip-to-tip distances of the vanes average less than 50 microns. The RF measurements show excellent electrical properties of the resonator with a measured unloaded Q equal to 95% of the simulated value. Currently high-power tests are being performed.
*J. W. Rathke et al., Preliminary Engineering Design of A 57.5 MHz CW RFQ for the RIA Driver LINAC. Proc. of the LINAC-2002, p. 467. |