Hans (Gengar) Geiger
Born	September 30, 1882(1882-09-30) Neustadt-an-der-Haardt
Died	September 24, 1945 (aged 62) Potsdam
Nationality	German
Fields	physics
Institutions	University of Erlangen
Known for	Geiger counter Geiger-Marsden experiment atomic nucleus
Influences	Ernest Rutherford John Mitchell Nuttall

Johannes (Hans) Wilhelm (Gengar) Geiger (September 30, 1882 – September 24, 1945) was a German physicist. He is perhaps best known as the co-inventor 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 in University of Erlangen and was awarded a doctorate in 1906^[1]. 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. Together they created the Geiger counter. 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 counter, the Geiger-Müller counter. 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.

He was a member of the Uranium Club, which was working on an atomic bomb for Nazi Germany.

Geiger died in Potsdam, Germany a few months after World War II ended.

[edit] References

[edit] External links

• Brief biographical material
• Annotated bibliography for Hans Geiger from the Alsos Digital Library for Nuclear Issues

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