Speaker
Description
Alpha decay is known for more than a century, however a global microscopic description of this process has only been successfully developed recently by Mercier et al. [1]. Within the framework of covariant energy density functional, using a least action principle, the half-life of medium and heavy nuclei agree within one order of magnitude with experimental value [2].
Moreover, a new type of decay was predicted: the double alpha decay, where two alpha particles are emitted simultaneously with a large relative angle. Their typical branching ratio (BR) of ~10-7 with respect to the single alpha decay, makes it experimentally accessible, these values of BR being those of well-known cluster decays already detected.
A dedicated experiment was held at Isolde in June 2023. A radioactive beam of 220-222Ra has been used to probe for possible double alpha decay of 220-222Ra as well as 216-218Rn. The setup consisted in 4 DSSD, which allows to make accurate spatial (and temporal) coincidences and therefore to drastically reduce the background due to single alpha decays. Results on this hunt will be shown.
[1] Mercier et al., PRL 127,012501 (2021)
[2] J. Zhao et al., PRC 107, 034311 (2023)
