R3B is an acronym for Reactions with Relativistic Radioactive Beams.
The R3B setup is part of the upcoming Facility for Antiprotons and Ions Research, FAIR, the future evolution of the GSI laboratory.
A large international collaboration including universities and research institutes is actively working on the realisation of the R3B experimental setup.
Actual status and future evolution
At the GSI, ions of any element up to uranium are bunched together to form an ion beam and accelerated up to velocities close to the speed of light (relativistic velocity). By shooting the ion beams on a suited target, unstable nuclides (radioactive nuclei) are produced and separated with the magnetic spectrometer FRS, forming secondary radioactive beams (also called rare isotope beams). The relativistic radioactive beams are used to study the properties of unstable nuclides and to perform nuclear reactions that give insight into the fundamental properties of nuclear matter and nuclear force. These reactions are also essential in astrophysics, since they are expected to take place in stars and exploding stellar environments such as supernovae. At the GSI laboratory, nuclear reactions with relativistic radioactive beams are currently studied with the LAND detection setup, which includes among the other detectors the homonymous LAND.
At FAIR, much higher intensities and velocities of the secondary beams will be achieved, also thanks to a more efficient magnetic spectrometer, the Super-FRS. The future R3B experimental setup will be adapted to the highest secondary-beam energies provided by the Super-FRS (resulting in different technical constrains with respect to the existing FRS). Although the R3B experimental configuration is based on a concept similar to the existing LAND reaction setup, substantial improvement with respect to resolution and an extended detection scheme will be introduced. Additional detectors are foreseen for the detection of light (target-like) recoil particles and for the tracking of heavy-ion trajectories and precise momentum measurements (placing a high-resolution magnetic spectrometer behind the large-acceptance dipole).
The R3B setup, once completed, will represent a versatile system of detectors with high efficiency, acceptance, and resolution for kinematically complete measurements of reactions with high-energy radioactive beams.