rfq

1
REXEBIS
In the Electron Beam Ion Source (EBIS) the 1
ions are charge bred. The positive ions are
trapped in an electron beam which knocks out
electrons from the ions.

• EBIS working principleThe positive ions are
  injected from the right and confined - radially
  in the potential well from a dense electron beam
  which is focused by a strong solenoidal magnetic
  field - longitudinally by two electrical
  potential barriersInside the beam the ions
  perform axial, magnetron and cyclotron motions in
  an entangled way, as well as collide with other
  ions.

EBIS cross-view

• Charge developmentDuring the confinement period
  (?s to seconds), the ions are continuously
  bombarded with fast moving electrons from the
  electron beam. These knock out the electrons from
  the ions. When the desired charge state is
  reached, the ions are extracted to the right by
  applying an extraction voltage.
• Obtained charge state

Axial potential
Radial potential
2
REXEBIS
The REXEBIS is based on a 2 T superconducting
solenoid. An immersed gun produces the electron
beam and the electrons are absorbed in an
iron-shielded collector. After a ?confinement lt
20 ms a q/A gt 1/4 is reached.
filling tower
collector position
racks
insulator
electron gun position
injection/extraction optics
magnet iron shield
turbo pumps
60/20 kV platform

• The REXEBIS platform is switched between 60 kV
  (at injection) and 20 kV (at extraction) to
  convert the ISOLDE energy (60 keV) to 20 keVq
  in accordance with accelerator specifications.

• REX-EBIS data
• B 2 TEelectron 5 keV?confinement lt 20 msIe
  0.5 Aje 250 A/cm2Ltrap lt 0.8 mWarm
  boreq/A 1/4