Low-energy nuclear physics at ALTO : beta-decay and friends

par Guillem Tocabens (IJCLab)

jeudi 26 mars 2026, 14:00 → 15:00 Europe/Paris

100/2-A201 - Salle A201 (IJCLab)

β-decay spectroscopy measurements are usually the first ones to be carried out on exotic nuclei. Despite their relative simplicity, they allow access to global observables (half-lives T1/2, delayed emission probabilities Pn/P2n, Qβ) but also to spin, transition rates and lifetimes of excited states in daughter nuclei. All these observables are used to test and constrain theoretical models aiming at describing nuclear structure. At the ALTO facility (Accélérateur Linéaire et Tandem à Orsay) neutron-rich radioactive ion beams are produced using the ISOL (Isotope Separation On-Line) technique, based on the photofission of uranium targets irradiated with a 50 MeV electron beam. These beams are then delivered to one of three setups dedicated to β-decay spectroscopy, allowing the observation of all emission products after radioactive decay of the produced exotic beam : COeCO (electrons), BEDO (gammas) and TETRA (neutrons). The ALTO β-decay scientific program is focused around two main themes which will be discussed in this seminar : nuclear structure around and above the neutron separation threshold and shape coexistence at low-energy. In addition to decay spectroscopy, the two other pillars of low-energy nuclear physics are represented in MLLTRAP (ion manipulation) for mass measurements, as well as POLAREX and LINO (hyperfine structure) for nuclear orientation and laser spectroscopy. These last three setups, once they enter their operation phase, will allow the extension of the physics program in the mass region relevant at ALTO. They will give access to others observables which are unreachable with the already running β-decay setups and add to the uniqueness of the ALTO facility.