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Accueil du site > ANGLAIS > Research > Exotic Nuclei > Research topics > Spectroscopic studies of proton rich nuclei


Spectroscopic studies of proton rich nuclei

(september 2012)

When going far from beta stability, the available energy for radioactive decay increases (Qbeta value), and for proton-rich isotopes, the proton separation energy SP decreases.

The decay (\beta+ or electron capture EC) can then populate excited states above SP in the daughter nucleus that can emit a subsequent proton. With increasing excitation energy of populated states, the delayed proton emission (after \beta decay) first concurrences, then replaces, the electromagnetic (\gamma emission) de-excitation. For even more exotic isotopes, the delayed 2- or 3-proton emission becomes possible (\beta-2p. \beta-3p).


Illustration showing a possible decay scheme for very proton-rich nuclei

The isotopes are produced using fragmentation reactions and implantation in a silicon detectors setup, or using ISOL technique and collecting the nuclei inside the detection setup.

The measurement of protons and gamma-rays emitted during the decay process allows to build the decay scheme of those nuclei. This kind of spectroscopic studies allows to investigate a wide range of topics concerning nuclear physics, such as :
- decay half-lives;
- beta transition strengh distribution ;
- ground states mass differences and analog states masse using IMME;
- isospin mixing of proton emitting states;
- search for direct 2-proton emission components (without involving any intermediate state)
- ...