Author: Obermayer, M.A.
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TUPVA074 Status of the modulated 3 MeV 325 MHz Ladder-RFQ 2249
 
  • M. Schütt, M.A. Obermayer, U. Ratzinger, M. Syha
    IAP, Frankfurt am Main, Germany
 
  Funding: BMBF 05P12RFRB9
Based on the positive results of the unmodulated 325 MHz Ladder-RFQ from 2013 to 2016, we develop a modulated 3.3 m Ladder-RFQ. The unmodulated Ladder-RFQ features a very constant voltage along the axis. It could withstand more than 3 times the operating power of which is needed in operation at a pulse length of 200μseconds. That corresponds to a Kilpatrick factor of 3. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the p-linac at FAIR. This particularly high frequency for a 4-Rod-type RFQ creates difficulties, which are challenging in developing an adequate cavity. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. Inspired by the successful rf power test, the nominal vane-vane voltage was increased from 80 kV to 96 kV. The basic design and tendering of the RFQ has been successfully completed in 2016. EM simulations of a modulated full structure, especially in terms of field-flatness and frequency tuning, will be shown. Furthermore, the mechanical design including a direct cooling of the structure for duty cycles up to about 5% will be discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA074  
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TUPVA075 Beam Dynamics for a High Current 3 MeV, 325 MHz Ladder-RFQ 2252
 
  • M. Syha, M.A. Obermayer, U. Ratzinger, M. Schütt
    IAP, Frankfurt am Main, Germany
 
  Funding: BMBF 05P12RFRB9
After the successful measurements with a 0.8 m prototype (see Fig. 1), a 3.3 m Ladder-RFQ is under construction at IAP, Goethe University Frankfurt. It is designed to accelerate protons from 95 keV to 3 MeV according to the design parameters of the Proton Linac at FAIR. The development of an adequate beam dynamics design was done in close collaboration with the IAP resonator design team. A constant vane curvature radius and at the same time a flat voltage distribution along the RFQ was reached by implantation of the modulated vane geometry into CST Microwave Studio RF field simulations. Points of reference for the beam dynamics layout are the beam dynamics designs of C. Zhang* and A. Lombardi**. The Code RFQGen*** was used for the beam dynamics simulations. In order to increase the transmission and to reduce the longitudinal and transversal exit emittances, the evolution of the modulation parameter m within the first 90 cells was investigated in detail. This paper presents the simulation results of this study.
* Chuan Zhang, Beam Dynamics for the FAIR Proton-Linac RFQ, IPAC 2014, Dresden
** C. Rossi et al., The Radiofrequency Quadrupole Accelerator for the LINAC4, LINAC08, Victoria, BC, Canada
***L. Young, RFQGen User Guide, Los Alamos Scientific Lab., NM (USA), 2016.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA075  
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