SCIENTISTS CREATE A WEIRD NUCLEUS THAT VANISHES IN NANOSECONDS
Physicists in Finland have created a pumpkin-shaped atomic nucleus that throws off protons in a rare kind of radioactive decay. Lutetium-149 has the shortest half-life of any of a group of radioactive elements called proton emitters. It loses half its radioactivity in a mere 450 nanoseconds. Lutetium is a rare-earth element that occurs as a silvery metal with 71 protons and 71 neutrons in its nucleus. It usually occurs alongside the metallic element ytterbium in Earth’s crust.
The new isotope, lutetium-149, has 71 protons and 78 neutrons. The scientists found that lutetium-149 was weird. For one thing, its nucleus isn’t a neat sphere, but rather a squashed sphere that looks a bit like a pumpkin. This is known as oblate distortion, and lutetium-149 is the most distorted nucleus ever measured. Its tiny half-life is also significantly shorter than isotope lutetium-151’s half-life of 80.6 milliseconds.
The researchers created the isotope by firing an isotope of nickel-58 at an isotope of ruthenium-96. The new lutetium isotope decays to ytterbium-148, which itself doesn’t stick around for long – it has a half-life of 250 milliseconds.