Introduction: Why ISOL@MYRRHA?

Radioactive ion beam research has been recognized as one of the top priorities in nuclear physics. Furthermore, radioactive ion beams (RIBs) create a wide area of research opportunities in other fields, like nuclear astrophysics, condensed matter research, atomic physics, fundamental interactions, as well as specific applications in, e.g., nuclear medicine.

Worldwide several efforts are underway to upgrade existing and to construct new second-generation facilities. Radioactive ion beams of isotopes covering a substantial part of the nuclear chart will be available with energies ranging from 0.025 eV (essentially room temperature) up to several GeV/u. They are produced using two complementary methods:

• The Isotope Separator On Line (ISOL) method 

The exotic nuclei are produced by spallation, fission or fragmentation reactions of a light projectile with a thick target. The reaction products diffuse out of the target through the transfer line towards the ion source, where they are ionized, and subsequently extracted, mass-separated on-line and (in some cases) reaccelerated. High-quality and intense beams of short-lived isotopes from a selected number of elements are available for experiments.

 • The in-flight method 

The exotic nuclei are produced by the fragmentation of a high-energetic, heavy projectile on a thin target. The reaction products, emerging with beam-like velocities, are then separated in-flight. This very fast method allows, amongst others, the production of very short-lived isotopes but the ion optical beam quality is somewhat limited.

Isotope Separator On Line (ISOL) method

In-flight method

Because of the wide spectrum of different scientific programs using RIBs, the demand for beam time is extra-ordinary resulting in typical beam-time periods of one to two weeks. On the other hand, going more and more exotic is a driving incentive of several research programs. Thus even vigorous efforts to improve beam intensity and purity, and detection efficiency and sensitivity will not substantially decrease the demand of beam time. This limitation prohibits potentially very interesting programs, involving experiments which:

  • need very high statistics;
  • need many time-consuming systematic measurements;
  • hunt for very rare events;
  • have an inherent limited detection efficiency.

These particular experimental programs can be uniquely addressed at ISOL@MYRRHA, given the availability of extended beam times (several weeks up to months) with high intensity (100-200 μA protons) and the high reliability of the MYRRHA accelerator.

More information on the MYRRHA accelerator can be found on the MYRRHA website.