IAP, Frankfurt am Main
GSI, Darmstadt
The 'Combined Zero-Degree Structure' ('Kombinierte Null Grad Struktur - KONUS') beam dynamics concept is described in detail. A KONUS period consists of a quadrupole triplet or a solenoid lens, a rebuncher section at negative synchronous phase and a multi cell zero degree synchronous particle main acceleration section. This concept is especially effective when applied for accelerator designs using H-mode resonators with ‘slim’ drift tubes which carry no focusing elements. The definition and typical ranges of KONUS lattice parameters are discussed on a general level, as well as on the basis of examples for realized or planned high current accelerators, like the GSI High Current Injector (HSI), the 70 mA, 3-70 MeV Proton Injector for the FAIR Facility and our proposal of a 125 mA D+, 5-40 MeV superconducting CH-DTL section for the International Fusion Materials Irradiation Facility (IFMIF).
IHEP Beijing, Beijing
The Rapid Cycling Synchrotron of the China Spallation Neutron Source is a high intensity proton machine, with the accumulated particles of 1.9*1013. The injection by the H- stripping method is performed in one of the four long uninterrupted dispersion-free straight-sections. The phase space painting technique is used for all the three phase planes to alleviate the space charge effects. In order to reduce the beam loss during the injection, the transverse and longitudinal halo of the linac beam is collimated in the Linac Ring Beam Transport line. The transverse beam halo collimation is based on a method of using periodic triplet cells and foil scrapers, which has the advantages of low beam loss in the beam line, deep halo collimation allowing almost no H- particles missing the injection foil, and possible proton applications of the scraped beam halo. A new simulation code SCOMT has also been developed to tackle the transfer, conversion and multiple scattering of the mixed H-, H0 and proton beams in the beam line. The large momentum spread of the linac beam is reduced by a debuncher and the longitudinal beam halo is collimated by a momentum collimator in the bending section.