Hans Geiger

Johannes Wilhelm Geiger, known as Hans, was a German experimental physicist who lived from 1882 to 1945. He is known as the inventor of the Geiger counter, a device used to detect ionizing radiation, and for carrying out the Rutherford scattering experiments, which led to the discovery of the atomic nucleus. He also performed the Bothe-Geiger coincidence experiment, which confirmed the conservation of energy in light-particle interactions. He was the brother of the meteorologist and climatologist Rudolf Geiger.