Paper 
Title 
Page 
MOP12 
KONUS Beam Dynamics Design of a 70 mA, 70 MeV Proton CHDTL for GSISIS12

60 

 R. Tiede, G. Clemente, H. Podlech, U. Ratzinger
IAP, FrankfurtamMain
 W. Barth, L. Groening
GSI, Darmstadt
 Z. Li
IMP, Lanzhou
 S. Minaev
ITEP, Moscow



The future scientific program at GSI needs a dedicated proton injector into the synchrotron SIS, in order to increase the proton intensity of the existing UNILAC/SIS12 combination by a factor of 70, resulting in 7· 10^{12} protons in the synchrotron. A compact and efficient 352 MHz RFQ  CHDTL combination based on novel structure developments for RFQ and DTL was worked out. For DTLs operated in an Hmode like CHcavities (H210mode), the shunt impedance is optimized by use of the KONUS beam dynamics. Beam dynamics simulation results of the CHDTL section, covering the energy range from 3 to 70 MeV, with emphasis on the low energy front end are presented. Optimization aims are the reduction of emittance growth, of beam losses and of capital costs, by making use of the high acceleration gradients and shunt impedance values provided by the Crossbar HType (CH) structure. In addition, the beam dynamics design of the overall DTL layout has to be matched to the power limits of the available 352 MHz power klystrons. The aim is to power each cavity by one klystron with a peak rf power of around 1 MW.


MOP20 
Design of the R.T. CHCavity and Perspectives for a New GSI Proton Linac

81 

 Z. Li
IMP, Lanzhou
 W. Barth, K. Dermati, L. Groening
GSI, Darmstadt
 G. Clemente, H. Podlech, U. Ratzinger, R. Tiede
IAP, FrankfurtamMain



The CHStructure has been studied at the IAP Frankfurt and at GSI for several years. Compared with the IH structure (H110mode), the CH structure (H210mode) can work at higher frequency (700 MHz) and can accelerate ions to higher energy (up to 150 AMeV). Detailed Microwave Studio (MWS) simulations were performed for this structure. Since a multigap cavity can be approximated as a quasiperiodic structure, it is possible to analyze one βλ/2cell at an energy corresponding to the cavity center. Additionally, a reduced copper conductivity of 85% was assumed. Geometry variations with respect to rf frequency and shunt impedance can be performed rapidly by that method in the first stage of optimization. Effective shunt impedances from 100 MΩ/m down to 25 MΩ/m were obtained for the energy range from 5 AMeV to 150 AMeV by this method. The rf frequency was 350 MHz up to 70 MeV and 700 MHz above. A systematic analysis of the influence of the cell number in long CH cavities on the effective shunt impedance is presented. The possibility to apply this structure to a 70 mA, 70 MeV, 352 MHz proton linac for GSI is discussed.

