Rarest nucleus reluctant to decay

Tantalum-180m’s half-life is more than a million times universe’s age

High Activity Disposal Experimental Site

LONG WAIT  Scientists searched for the decay of nature’s rarest type of atomic nucleus, tantalum-180m, at the High Activity Disposal Experimental Site, or HADES, laboratory (shown above) located 225 meters underground in Mol, Belgium. 

Guillaume Lutter

Nature’s rarest type of atomic nucleus is not giving up its secrets easily.