Alpha particle types: eventually named alpha, beta, and gamma by Rutherford, based on penetration of objects and deflection by a magnetic field. Alpha rays were defined by Rutherford as those having the lowest penetration of ordinary objects. Rutherford's work also included measurements of the ratio of an alpha particle's mass to its charge, which led him to the hypothesis that alpha particles were doubly charged helium ions (later shown to be bare helium nuclei). In 1907, Ernest Rutherford and Thomas Royds finally proved that alpha particles were indeed helium ions. To do this they allowed alpha particles to penetrate a very thin
Pirkko Eskola using the Heavy Ion Linear Accelerator, bombarding a target of californium-249 with nitrogen nuclei. There was debate between Russia and America over who first discovered of Rutherfordium. Erkola studied the alpha decay of Nobelium 255 and 257. She went on to work on beta-unstable Alpha particle emitting nuclei. Using Alpha-particle spectroscopy she studied lawrencium isotopes 255 - 260 and Mendelevium isotopes 248 - 252. Her husband, Kari Eskola, was a professor of physics at the University of Helsinki. She went on to have a career in science education. She was an editor of the Finnish Physical Society journal "Physica Fennica".