Using the focal-plane spectrometer of the gas-filled recoil separator at the Accelerator Laboratory of the University of Jyväskylä in Finland, physicists have observed two decay events of the new isotope astatine-188 (188At), which consists of 85 protons and 103 neutrons. Kokkonen et al. report the discovery of the new atomic nucleus 188At, which is the heaviest proton-emitting isotope known to date. “Proton emission is a rare form of radioactive...
