Early years Johannes Wilhelm Geiger was born on 30 September 1882 in
Neustadt an der Haardt, Germany, the son of Indologist
Wilhelm Geiger. In 1902, Geiger started studying physics and mathematics at the
University of Erlangen, receiving his
Ph.D. in 1906 with a thesis on
electric discharges. After graduating, Geiger received a fellowship to the
University of Manchester, where he worked as an assistant to
Arthur Schuster. In 1907, after Schuster's retirement, Geiger began to work with his successor,
Ernest Rutherford, and in 1908, along with
Ernest Marsden, conducted the famous
Geiger–Marsden experiment (also known as the "gold foil experiment"). This process allowed them to count
alpha particles
Middle years In 1912, Geiger was named head of radiation research at the Physikalisch-Technische Reichsanstalt (now the
Physikalisch-Technische Bundesanstalt) in
Charlottenburg, where he worked with
James Chadwick and
Walther Bothe (winners of the 1935 and 1954
Nobel Prize in Physics, respectively). Work was interrupted when Geiger served in the German military during
World War I as an artillery officer from 1914 to 1918. In 1924, Geiger and Bothe carried out the
Bothe–Geiger coincidence experiment that confirmed the
Compton effect, which helped earn
Arthur Compton the 1927 Nobel Prize in Physics. In 1925, Geiger began a teaching position at
Kiel University. In 1928, Geiger and his student,
Walther Müller, created the
Geiger–Müller tube. This new device not only detected alpha particles, but also
beta and
gamma particles, and is the basis for the
Geiger counter. In 1929, Geiger was appointed Professor of Physics and Director of Research at the
University of Tübingen, where he made his first observations of a
cosmic ray shower. In 1936, he took a position at Technische Hochschule Berlin (now
Technische Universität Berlin), where he continued to research cosmic rays,
nuclear fission, and artificial radiation until his death in 1945. Geiger endured the
Battle of Berlin and subsequent
Soviet occupation in April/May 1945. A couple of months later he moved to
Potsdam, where he died on 24 September 1945 at the age of 62. == Awards ==