The TRIUMF 500 MeV cyclotron: present operation and intensity upgrade

A new series of experiments (mainly astrophysics) began at TRIUMF in July 2001 when the ISAC-I linear accelerator began delivering up to 1.5 MeV/u radioactive ion beams (RIB) to users. A superconducting linear accelerator extending the RIB energy to 6.5 MeV/u has recently been approved and is now being constructed (ISAC-II). Record RIB intensities are being achieved from different target ion sources with a primary incident proton beam of 500 MeV, up to 50 μA intensity. This will later be increased to 100 μA, compatibly with target acceptance. Furthermore, an additional 100 μA extracted proton beam is being considered for simultaneous (RIB) production from a second target-ion source system. This would significantly enhance the research potential of the laboratory. Four simultaneous high-intensity extracted beams would therefore be required for a total maximum cyclotron accelerated current of about 400 μA. Recently we have been able to deliver 300 μA to the existing three high intensity beam lines at 90% duty cycle. The cw delivery of beam was limited only by the presently available external beam dump capacity. In this paper we will review the present operational experience at 200/250 μA, the future plans for intensity upgrade to 350/400 μA, and the intrinsic factors limiting the total accelerated intensity beyond 400 μA.