The Canadian Rare Isotope facility with Electron Beam ion source (CANREB) is an essential part of the Advanced Rare IsotopE Laboratory (ARIEL) presently under construction at TRIUMF. CANREB was recently commissioned and can accept stable or rare isotope beams from a variety of ion sources, delivering high purity beams of highly charged ions (HCI) to experiments. The injected beams are bunched using a radiofrequency quadrupole cooler-buncher and energy adjusted using a pulsed drift tube for injection into the electron beam ion source (EBIS) charge state breeder. The EBIS is designed for a maximum electron beam current of 500 mA and a maximum magnetic field of 6 T. Ions with energies up to 14 keV can be injected and HCI with mass-to-charge (A/q) ratios 3 ⩽ A/q ⩽ 7 can be charge bred and extracted. The HCI are A/q-selected using a Nier-type spectrometer before being transported to the ISAC linac for post-acceleration. Results from CANREB beam commissioning with focus on the EBIS will be presented.

OmniTrak simulations were performed in the 40°K injection-extraction region near the collector trumpet of the CANREB EBIS to understand the nature of chronic electrical breakdowns of PEEK feedthroughs. These feedthroughs are designed to route high-voltage wires (up to +15 kV) from room temperature to each drift-tube at 4°K, while operating in the strong superconducting semi-Helmholtz field. The electric field strength |E| at the PEEK feedthroughs are ∼ 7 × 105 V/m within about 2-3 mm of the surroundings at ground potential. When simulating only bare wires (with no PEEK feedthroughs), |E| increases by about 1 order-of-magnitude to > 106 V/m in the same region. Assuming a 3 Tesla magnetic field, electrons starting with 0 eV near the PEEK feedthroughs undergo helical motions due to E → × B → -drift and demonstrate reflections from magnetic mirror effects. A combination of this helical motion, reflecting mirror trajectories, and attraction of electrons to exposed HV wires may be responsible for the ongoing HV breakdown of insulating feedthroughs in this region of the EBIS. Solving this problem requires complete ground-shielding of all HV wiring to eliminate |E| and should encapsulate all wires to prevent breakdown paths.