Concept of a High-resolution Online Mass Separator for the Munich Fission Fragment Accelerator

A fission fragment accelerator combined with the Munich high-flux reactor FRM-II is under design for the delivery of intense beams of mass separated very neutron-rich fission fragments with energies at the Coulomb barrier They can be used to produce very heavy neutron-rich nuclei in fusion reactions. The large neutron excess will result in much longer lifetimes of the produced heavy elements, compared to neutron-deficient ones produced in reactions with stable nuclear beams. Thus fast a-chains can no longer be used to identify the heavy reaction products. A new separator will be used consisting of a velocity filter, an ion guide system (IGISOL) and a Penning trap. The velocity filter separates the primary beam and results in a strong background suppression. The IGISOL system improves the emittance and enriches the 1(+) ions in the beam, which will then be efficiently transferred into a Penning trap. In the Penning trap the ions are bunched, stopped and mass separated with high resolving power (R approximate to 10(5)).