First transuranic synthesized (1940). ²³⁷Np is long-lived (~2.14 Myr) and is the start of the only fully extinct primordial decay chain (the 4n+1 series).
First transuranic synthesized (1940). ²³⁷Np is long-lived (~2.14 Myr) and is the start of the only fully extinct primordial decay chain (the 4n+1 series).