Hans Geiger
In 1902, Geiger started studying physics and mathematics at the University of Erlangen and was awarded a doctorate in 1906. In 1907 he began work with Ernest Rutherford at the University of Manchester and in 1909, along with Ernest Marsden, conducted the famous Geiger–Marsden experiment called the "gold foil experiment". Rutherford and Geiger created the Rutherford-Geiger tube, later to become the Geiger tube.