STATUS OF THE 70 MeV, 70 mA CH PROTON-DTL FOR FAIR

摘要

The CH-type cavity shows promising features in the low and medium beta range: its high accelerator gradient and the high level of shunt impedance together with the compact transverse dimensions make this new cavity a good candidate for proton acceleration up to 100 MeV. That's why GSI has decided to base the new high current proton injector for the new FAIR facility on that structure: the operating frequency will be 352 MHz with an injection energy of 3 MeV. In order to improve the technical experience on this new kind of structure, IAP has built a model consisting of 8 equidistant gaps for a total cavity-length of 60 cm. Several design options with respect to welding, alignment, cooling and RF joints were studied and compared with each other. A new concept for the end-cells geometry will result in the desired flatness of the electric field along the cavity axis and, at the same time, allows an effective integration of internal quadrupole lenses. Finally, the electric quadrupole content of CH-structure gaps is listed in dependence on the geometry of the cell.