First two operational years of the electron-beam ion trap charge breeder at the National Superconducting Cyclotron Laboratory

Abstract

The electron-beam ion trap (EBIT) charge breeder of the ReA post-accelerator, located at the National Superconducting Cyclotron Laboratory (Michigan State University), started on-line operation in September 2015. Since then, the EBIT has delivered many pilot beams of stable isotopes and several rare-isotope beams. An operating aspect of the ReA EBIT is the breeding of high charge states to reach high reaccelerated beam energies. Efficiencies in single charge states of more than 20% were measured with 39 K 15þ , 85 Rb 27þ , 47 K 17þ , and 34 Ar 15þ. Producing high charge states demands long breeding times. This reduces the ejection frequency and, hence, increases the number of ions ejected per pulse. Another operating aspect is the ability to spread the distribution in time of the ejected ion pulses to lower the instantaneous rate delivered to experiments. Pulse widths were stretched from a natural 25 μs up to ∼70 ms. This publication reviews the progress of the ReA EBIT system over the years and presents the results of charge-breeding efficiency measurements and pulse-stretching tests obtained with stable-and rare-isotope beams. Studies performed with high sensitivity to identify and quantify stable-isotope contaminants from the EBIT are also presented, along with a novel method for purifying beams.

K38 isomer production via fast fragmentation

“…Fig. 4), an effect of the breeding time and not the rate of the stopped beam [23]. This indicates that the rate of contaminants in the beam of interest should be smaller than ∼3000=8000 by at least the true attenuation factor, in addition to any gains in the intensity of the incoming (stopping) beam.…”

“…Reducing the A1900 momentum acceptance from its maximum 5.5% to 0.5% using the momentum slits allowed for the momentum distribution to be sampled more precisely without each step overlapping. This mixed g þ i beam was then stopped in the Argonne Gas Stopper [21] and charge bred to 17þ in the electron-beam ion trap (EBIT) [22,23], which is the optimum charge state for charge breeding efficiency, minimization of contaminants, and matching the q/A range of the ReA linac. Beta decay implantation counters were placed at the end of the A1900, after the Argonne Gas Stopper, and after the EBIT, to measure the ratio of isomer to ground state.…”

High-Current Capability and Upgrades of the EBIS/T Charge-Breeding System in the Reaccelerator at the Facility for Rare-Isotope Beams

“…The FRIB reaccelerator (ReA) [1] utilizes a charge-breeding system at its front end, which includes a Beam Cooler/Buncher (BCB) and an Electron-Beam Ion Trap (EBIT) [2]. The EBIT electron current is a factor limiting its capacity to ∼2×10 10 elementary charges.…”

Main magnetic focus ion source: Device with high electron current density

“…At present, highly charged ions are the subject of extensive research and numerous applications in atomic, nuclear, and particle physics [1][2][3][4][5][6][7][8]. High-quality beams of ions with different ionization degree for any elements and isotopes, stable and radioactive, are required.…”