CANREB EBIS commissioning at TRIUMF

Abstract

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.

High-voltage breakdown in the injection-extraction region of the CANREB EBIS: A possible mechanism

“…However, with magnetic field, the situation became progressively worse where the feedthroughs could only tolerate ∼7 kV in a 1 T magnetic field. Higher magnetic fields and higher voltages worsened the electrical breakdown; voltages >7 kV were not possible to achieve at 1 T. This operation is significantly below the EBIS design specs (15 kV and 6 T) and are limiting the achievable extracted ion energy [5].…”

Pulse-stretching out of the CANREB EBIS

“…A detailed description of the CANREB EBIS can be found in [2]. Commissioning results of the CANREB facility have been presented in [3]. 1, between a high potential V high (470 V or 490 V depending on cases) to a low potential V low (160 or 290 V depending on cases).…”

Improvement of the FEBIAD ion source at SPIRAL1

“…Once released by the target as atoms, the radioactive isotopes are ionized by a source, which is chosen regarding its ability to ionize chemical elements of interest. Among existing source principles, the Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source offers a large ionizing spectra and has therefore been implemented in several ISOL leading facilities as at ISOLDE CERN [1], ISAC TRIUMF [2], JAEA ISOL [3], and in 2012 at GANIL/SPIRAL1 to extend its beam offer. All these sources are based on the design initially developed by R. Kirchner [4], which uses the electron emission principle of hot metals firstly observed by Edison at the end of the 19 th century and later studied by Richardson [5].…”