Research on nuclear structure far from stability is one of the most exciting frontiers in nuclear physics.
REX-ISOLDE (Radioactive Ion Beam Experiment) uses the method of charge-state breeding to enhance the charge state of the ions before injection into a linear accelerator. The charge multiplication of the radioactive ions allows access to the heavier mass region of the nuclear chart, which cannot be reached by accelerating monocharged ions. REX-ISOLDE makes use of the large variety of radionuclides that have been extracted from the on-line mass separator ISOLDE.

The radioactive singly-charged ions from the separators are first accumulated, bunched and cooled in a Penning trap, REXTRAP. The trap stores the ions during the breeding in the subsequent charge breeder.

 

REXTrap

Principle: Cooling (10-20 ms) with Buffer Gas & RF Result: Bunched and cooled beam. It is a Penning Trap of REX and HIE-ISOLDE.

Bunches of ions are then transferred to an electron beam ion source, REXEBIS where the ions are charge bred to a mass-to-charge ratio below 4.5.

 

REXEbis

Principle: Ions trapped and ionisated by e- bombardment Result: Produces multiple charged ions (freq. 5ms-1s ).  It is a charge breeder of REX and HIE-ISODLE.

Finally, the ions are injected into a compact linear accelerator via a mass separator.

 

Mass separator

Result: A/q separator A/q resoltion ~150

The normal conducting linear accelerator has a total length of about 11 m. It consists of a Radio Frequency Quadrupole (RFQ) accelerator which accelerates ions from 5 to 300 keV/u, a rebuncher section, an Interdigital H-type (IH) structure that boosts the energy to 1.2 MeV/u, three seven-gap spiral-resonators and a 9-gap IH resonator, which allow the variation of the final energy between 1.2 and 3 MeV/u.

 

LINAC (300KeV/u...3.0MeV/u)

Result: A/q separator A/q resoltion ~150

A superconducting linear accelerator, which is started operation in 2015, downstream the normal conducting accelerator (HIE-ISOLDE). With this new accelerator post-accelerated radioactive ion beams with up to 10 MeV/u (A/q = 4.5) is available at ISOLDE.

 

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