Characterizing the Radioactive Ion Beams Produced at the CERN-ISOLDE Facility

by Dr Niels Killian Noal Bidault (CERN)

Thursday Mar 30, 2023, 3:30 PM → 5:00 PM Pacific/Honolulu

112 (Watanabe Hall)

ISOLDE (Isotope Separator On-Line DEvice) is an experimental research facility within CERN
(European Organization for Nuclear Research), where beams of radioactive isotopes are produced
and accelerated for studies in fundamental and applied physics. The radioactive nuclides result from
collisions between a fixed target and an incident proton beam at 1.4 GeV. After that, beams of stable
or radioactive isotopes are prepared for delivery to experimental stations at low energy (< 60 keV) or
high energy (< 10 MeV/u) using the REX/HIE-ISOLDE linear accelerator. Post-acceleration implies
using the REX-EBIS (Electron Beam Ion Source), in which ions are trapped to reach higher charge
states via electron impact ionization in the keV range.
The achievement of high-precision experiments with ion beams necessitates optimal intensity,
purity, energy distribution, and transverse emittance. The colloquium first covers the aspects of ion
and electron beam physics required for comprehending the methods of characterization and
optimization. We then present experimental methods to measure and improve the beam quality of
low-energy ion beams, of the REX-EBIS electron beam immersed in an ion cloud and finally of post-
accelerated ion beams. The concepts presented help maximize the facility’s scientific output by
providing shorter-lived radioactive beams of higher quality to experimental stations.

Video-Dr. N. Bidault