*2.1. Low Energy Facilities*

Highly-intense beams of stable isotopes are available at several facilities such as GANIL (Large Heavy Ion National Accelerator, Caen, France) [25], Jyväskylä University [26], Argonne National Laboratory (ANL) [27] and INFN (National Institute for Nuclear Physics, Italy) Legnaro [28], to name only a few. These low-energy accelerators serving fusion-evaporation or multi-nucleon-transfer reactions newly-applied also in the 100Sn region [29], play a very important role when combined with highly-efficient detectors.

Such a combination was recently available at GANIL [25] with AGATA [30,31] and ancillary detectors as e.g., DIAMANT [32,33] and NEDA [34,35], which make the exit channel identification possible. Alternatively, a recoil spectrometer such as VAMOS [36–38], MARA [39], or the FMA [40] may serve for residue identification. A clear advantage of this method is prompt spectroscopy at the reaction target tagged with identified recoils or a decay particle (e.g. *γ, β, α*).

Often, population of high-spin states, in particular in fusion-evaporation reactions, is considered advantageous. However, in the 100Sn region the most exotic nuclei that can be investigated are produced in 2-neutron (2*n*) or more and 2*nα* exit channels [41]. Those residues are produced with the highest cross section at relatively low energies above the Coulomb barrier keeping the total reaction cross section low in order to avoid misidentification due to contaminants. At those lower energies, the reached spin values and residue excitation energy are reduced.

Impressive experiments of this type were performed in the last years leading to important discoveries, e.g., the delayed rotational alignment in a deformed *N=Z*88Ru [42]. Another way for the production of very neutron deficient Sn isotopes is alpha decay tagging measurements of the Te isotopes. The two leading groups at ANL with FMA [43,44] and at Oak Ridge National Laboratory (ORNL) [45,46] have been hunting for superallowed *α*-decay signatures for the last 15 years. The burning question—whether it is energetically possible to produce excited states in 100Sn in this way—remains open [47].
