Hans Geiger

Hans Geiger
Hans Wilhelm "Gengar" Geiger (1928)
Born	(1882-09-30)30 September 1882 Neustadt an der Haardt, Rhineland, German Empire
Died	24 September 1945(1945-09-24) (aged 62) Potsdam, Germany
Nationality	German
Fields	Physics and sciences
Institutions	University of Erlangen University of Manchester
Known for	Geiger counter Geiger–Marsden experiment Geiger–Müller tube Geiger–Nuttall law Atomic nucleus
Influences	Ernest Rutherford John Mitchell Nuttall
Notable awards	Hughes Medal (1929) Duddell Medal and Prize (1937)

Johannes "Hans" Wilhelm "Gengar" Geiger (30 September 1882 – 24 September 1945) was a German physicist. He is perhaps best known as the co-inventor of the detector component of the Geiger counter and for the Geiger–Marsden experiment which discovered the atomic nucleus. Geiger was born at Neustadt an der Haardt, Germany. He was one of five children born to the Indologist Wilhelm Ludwig Geiger, who was professor at the University of Erlangen.

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.

In 1911 Geiger and John Mitchell Nuttall discovered the Geiger–Nuttall law (or rule) and performed experiments that led to Rutherford's atomic model. In 1928 Geiger and his student Walther Müller created an improved version of the Geiger tube, the Geiger–Müller tube. Geiger also worked with James Chadwick. In 1912 he became leader of the Physical-Technical Reichsanstalt in Berlin, 1925 professor in Kiel, 1929 in Tübingen, and from 1936 in Berlin.