Upgrading of the CAESAR ion source at INFN-LNS

The CAESAR source is operating at INFN-LNS since 1999 and it has provided the most of light ions for the K-800 Superconducting Cyclotron, whereas the SERSE source is mainly devoted to the production of highly charged heaviest ions. Anyway, since the beginning the source behavior appeared to be not satisfactory in terms of the beam transmission to the Cyclotron and then the extraction system has been redesigned in order to decrease the emittance. The main features of the calculations carried out with KOBRA3D are described. Recently the injection section has been also re-designed, because of the poor results obtained when operating CAESAR (too high microwave power reflection and poor coupling to the plasma). The new setup has an improved axial confinement due to the insertion of adequate iron plugs and the coupling has been experimentally tested to be effective up to 18 GHz. The paper will describe the major mechanical design features together with the results achieved.