Further R&D For A New Superconducting Cw Heavy Ion Linac@GSI

A low energy beam line (1.4 MeV/u) behind the GSI High Charge State Injector (HLI) will provide cw-heavy ion beams with high beam intensity. It is foreseen to build a new cw-heavy ion LINAC for post acceleration up to 7.3 MeV/u. In preparation an advanced R&D program isdefined: The first LINAC section (financed by HIM andpartly by HGF-ARD-initiative) comprising a sc CH-cavity embedded by two sc solenoids will be tested in2014/15 as a demonstrator. After successful testing theconstruction of an advanced cryo module comprising fourCH cavities is foreseen. As an intermediate step towardsan entire cw-LINAC the use of a double of two CH-cavities is planned: A short 5 cell cavity should bemounted directly behind the demonstrator cavity inside ashort cryostat. The design of the cw LINAC based onshorter sc CH-cavities would minimize the overalltechnical risk and costs. Besides with this cavity anoptimized operation of the whole LINAC especially withrespect to beam quality could be achieved. Last but notleast the concept of continuous energy variation applyingphase variation between the two cavities with constantbeta profile could be tested