Status report of the radioactive ion beam production at TRIUMF (invited)

Abstract

The ISAC radioactive ion beam (RIB) facility has been operational since November 1998. The ISAC Facility at TRIUMF utilizes up to 100μA proton intensity at 500MeV from the existing H− cyclotron to produce RIB using the isotopic separation on-line (ISOL) method. The science programs at ISAC range from nuclear astrophysics to fundamental symmetry. The facility can deliver RIB to the low energy area and a linear accelerator composed of a four-rod radio frequency quadrupole and a linear accelerator can provide beam from A=3to30amu with an energy range from 0.15to1.5AMeV. An accelerator upgrade is underway and will allow us to extend the mass range to A=150amu and the energy up to 6.5AMeV. The target/ion source assembly and heavy-ion optics components are located in a shield canyon under 2m of steel shielding allowing high proton beam intensity on a thick target. At the beginning the production target was operating at 2–5μA but rapidly the proton beam intensity was raised to 40μA. Now, we operate up to nearly 100μA proton beam using the new high power target design equipped with radial fins. While the production target capabilities have improved quite a lot, from 2to100μA, the ion sources development have not followed the same trend. Since the beginning of ISAC most of the RIB production is done using the surface ion source. A 2.45GHz electron cyclotron resonance ion source (ECRIS) was built and used on line with moderate success.