Potential enhancement of alpha decay in metals at cryogenic temperatures

The influence of metallic environments and cryogenic temperatures on nuclear decay rates remains an open question in nuclear physics, with potential implications for both fundamental science and radioactive waste management. Following a review of experimental studies on environmental effects in beta decays, electron capture, and alpha decays, a phenomenological parametrization of electron screening effects is developed, taking into account competing theoretical predictions. The A-DREAM (Accelerated Depletion of RadioactivE wAste in Metals) project is then presented, aiming to investigate whether the alpha-decay rate of 226Ra can be enhanced at cryogenic temperatures when embedded in a metallic matrix. A wet-chemistry protocol was developed to produce low-activity (a few tens of Bq) sources of metallic 226Ra homogeneously incorporated into solid Ga-Hg alloy matrices, ensuring incorporation of Radium atoms into the metallic lattice in a structurally coherent manner, as well as long-term sample stability.