Initial commissioning of the ISAC RIB facility

Abstract

Construction began in 1995 on ISAC, a radioactive ion beam (RIB) and accelerator facility at TRIUMF that utilises the ISOL (on-line isotope separation) production method. ISAC includes: a new building, a beam line with adequate shielding to transport up to 100 uA of 500 MeV protons to two target/ion-source stations, remote handling facilities for the targets, a high-resolution mass-separator, linear accelerators and experimental facilities. The ISAC target/ion source station permits the production of nuclei far from stability over a large isotopic range with high luminosity. Ions from the target/ion-source can be transported at energies up to 60 keV through a low-resolution pre-separator magnet followed by a high-acceptance, high-resolution mass-separator magnet to a variety of low energy experimental stations. Alternatively, ions with q/A greater than or equal to 1/30 and an energy of 2 keV/amu can be bunched in the low energy beam transport line prior to a cw RFQ accelerator operating at 35 MHz. The 150 keV/amu beam from the RFQ is stripped and isotopes with a particular q/A greater than or equal to 1/6 are selected for acceleration in a DTL. The DTL is a separated function accelerator with five accelerating tanks and three split-ring bunchers operating cw at 105 MHz. The final energy will be variable from 0.15 to 1.5 MeV/amu. The accelerated beams will be used primarily for nuclear astrophysics studies. The beam commissioning of the proton beam line, target/ion source, mass separator and RFQ has started. The TRIUMF neutral atom trap (TRINAT) and a yield station began using the low energy ISAC beam in November 1998. The RFQ has accelerated stable ions up to 54 keV/amu. The first tank of the drift tube linac and the subsequent buncher have been commissioned at full rf power. Beam commissioning of the DTL is scheduled for the end of 1999. The full-energy RIB will become available for the DRAGON recoil spectrometer at the end of 2000. A new five-year plan that includes an upgrade of ISAC to permit acceleration of radioactive ions up to 6.5 MeV/amu for masses up to 150 amu has been presented for funding.