Recent Results with the 2.45 GHZ ECRIS at TRIUMF-ISAC

A 2.45 GHz ECRIS was built at TRIUMF for on-line applications at the ISAC facility. The ISAC facility utilizes a 500 MeV proton beam driver with intensity that can reach 100 μA on the isotope production target. In such an environment special care during the design phase had to be taken, all the ECRIS components especially the two coils had to be radiation hard. Following a disappointing run with a Ta foil target intensive studies were carried out to determine the relationship between the ionization efficiency and the gas pressure in the ion source. The Neon ionization efficiency decreased from 2% to 0.01% when the tank pressure surrounding the ECR increased from 1.5x10-6 to 3x10-6 Torr. This pressure increase corresponds to approximately 1014 Kr/s and 5x1013 Xe/s. In May 2004 additional on-line tests with a SiC target were undertaken. The goal was to produce 18Ne for a high precision half-live determination. Again when operating the ECRIS with the same operating parameters as the ones obtained off-line the ionization efficiency decreased when the target was bombarded with more that 5μA. After modifying the ECRIS operating conditions by injecting only Ar as a support gas and the proton beam could be increased up to 30 μA, which is the nominal for a SiC target