Hans Geiger

Geiger was born in 1882 in Neustadt an der Haardt. He was one of five children born to the Indologist Wilhelm Ludwig Geiger, who was a professor at the University of Erlangen. In 1902, Geiger started studying physics and mathematics at Erlangen and was awarded a doctorate in 1906.{{cite journal

|last1=Krebs

|date=July 1956

|title=Hans Geiger: Fiftieth Anniversary of the Publication of His Doctoral Thesis, 23 July 1906

|journal=Science

|volume=124

|issue=3213

|pages=166

| pmid = 17843412

|doi = 10.1126/science.124.3213.166

| bibcode = 1956Sci...124..166K

|first1=AT

}} His thesis was on electrical discharges through gases.{{Cite journal |pmc = 3228631|year = 2011|last1 = Shampo|first1 = M. A.|title = Hans Geiger—German Physicist and the Geiger Counter|journal = Mayo Clinic Proceedings|volume = 86|issue = 12|pages = e54|last2 = Kyle|first2 = R. A.|last3 = Steensma|first3 = D. P.|pmid = 22196280|doi = 10.4065/mcp.2011.0638}} He received a fellowship to the University of Manchester and 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{{cite journal |author1=Rutherford E. |author2=Geiger H. |year=1908 |title=An electrical method of counting the number of α particles from radioactive substances |journal=Proceedings of the Royal Society of London, Series A |volume=81 |issue=546 |pages=141–161 |url=https://books.google.com/books?id=jaezAAAAIAAJ&pg=PA141|doi=10.1098/rspa.1908.0065 |issn=1364-5021|bibcode = 1908RSPSA..81..141R |doi-access=free }}{{cite journal |author=Geiger H. |year=1913 |title=Über eine einfache Methode zur Zählung von α- und β-Strahlen (On a simple method for counting α- and β-rays) |journal=Verhandlungen der Deutschen Physikalischen Gesellschaft |volume=15 |pages=534–539 }}{{cite book |author=Campbell John |year=1999 |title=Rutherford Scientist Supreme, AAS Publications}} and led Rutherford to start thinking about the structure of the atom. He was elected to membership of the Manchester Literary and Philosophical Society on 29 November 1910.

In 1911, Geiger and John Mitchell Nuttall discovered the Geiger–Nuttall law (or rule) and performed experiments that led to Rutherford's atomic model.H. Geiger and J.M. Nuttall (1911) "The ranges of the α particles from various radioactive substances and a relation between range and period of transformation", Philosophical Magazine, series 6, vol. 22, no. 130, pages 613-621. See also: H. Geiger and J.M. Nuttall (1912) "The ranges of α particles from uranium", Philosophical Magazine, series 6, vol. 23, no. 135, pages 439-445.

In 1912, Geiger was named head of radiation research at the Physikalisch-Technische Reichsanstalt (Imperial Physical Technical Institute – PTR) in Charlottenburg. There he worked with Walter Bothe (winner of the 1954 Nobel Prize in Physics) and James Chadwick (winner of the 1935 Nobel Prize in Physics).{{cite web | url=https://www.aps.org/publications/apsnews/201206/physicshistory.cfm | title=June 1911: Invention of the Geiger Counter}} 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 Walther Bothe carried out the Bothe–Geiger coincidence experiment that confirmed the Compton effect, which helped earn Arthur Compton the 1927 Nobel Prize in Physics. Bothe would also receive the Nobel Prize in Physics for their experiment in 1954, after Geiger's death.{{Cite journal |last=Maier |first=Elke |date=2011 |title=Flashback: Particle Billiards, Captured on Film |url=https://www.mpg.de/4444392/MPR_2011_3 |journal=MaxPlanckResearch |volume=3 |pages=92–93}}

In 1925, he began a teaching position at the University of Kiel where, 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.{{cite journal |author1=Geiger |author2=Müller W. |year=1928 |title=Elektronenzählrohr zur Messung schwächster Aktivitäten (Electron counting tube for the measurement of the weakest radioactivities) |journal=Die Naturwissenschaften (The Sciences) |volume=16 |issue=31 |pages=617–618 |doi=10.1007/BF01494093 |issn=0028-1042 |bibcode = 1928NW.....16..617G |s2cid=27274269 }}See also:

1. Geiger, H. and Müller, W. (1928) "Das Elektronenzählrohr" (The electron counting tube), Physikalische Zeitschrift, 29: 839-841.
2. Geiger, H. and Müller, W. (1929) "Technische Bemerkungen zum Elektronenzählrohr" (Technical notes on the electron counting tube), Physikalische Zeitschrift, 30: 489-493.
3. Geiger, H. and Müller, W. (1929) "Demonstration des Elektronenzählrohrs" (Demonstration of the electron counting tube), Physikalische Zeitschrift, 30: 523 ff. Geiger was awarded the Hughes Medal in 1929 for this work.

In 1929, Geiger was named 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 with Technische Universität Berlin where he continued to research cosmic rays, nuclear fission, and artificial radiation until his death in 1945.

Beginning in 1939, after the discovery of nuclear fission, Geiger was a member of the Uranium Club, the German investigation of nuclear weapons during World War II. The group splintered in 1942 after its members came to believe that nuclear weapons would not play a significant role in ending the war.

Although Geiger signed a petition against the Nazi government's interference with universities, he provided no support to colleague Hans Bethe (winner of the 1967 Nobel Prize in Physics) when he was fired for being Jewish.{{cite web | url=https://www.atomicheritage.org/history/scientific-exodus | title=Scientific Exodus}}{{cite web | url=https://www.scientificamerican.com/article/how-2-pro-nazi-nobelists-attacked-einstein-s-jewish-science-excerpt1/ | title=How 2 Pro-Nazi Nobelists Attacked Einstein's "Jewish Science" [Excerpt]| website=Scientific American}}

Geiger endured the Battle of Berlin and subsequent Soviet occupation in April/May 1945. A couple of months later he moved to Potsdam, dying there on 24 September 1945.

• Geiger (crater)

{{Reflist}}

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• [https://web.archive.org/web/20060828132837/http://alsos.wlu.edu/qsearch.aspx?browse=people%2FGeiger%2C+Hans Annotated bibliography for Hans Geiger from the Alsos Digital Library for Nuclear Issues]

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Category:1882 births

Category:1945 deaths

Category:German nuclear physicists

Category:20th-century German inventors

Category:University of Erlangen-Nuremberg alumni

Category:People associated with the University of Manchester

Category:People from the Palatinate (region)

Category:Academic staff of Technische Universität Berlin

Category:Academic staff of the University of Kiel

Category:People from Neustadt an der Weinstraße

Category:20th-century German physicists