Hans Geiger

By-Upadhyay aditi- 09E243S.Yaadha-09E252

Childhood:

Johannes Wilhelm Geiger was born in Neustadt an- der- Haardt (now Neustadt ander-Weinstrasse), Germany, on September 30, 1882. His father, Wilhelm Ludwig Geiger, was a professor at the University of Erlangen from 1891 to 1920.

His Education: Geiger was educated first at Erlangen Gymnasium, from which he graduated in 1901. After completing his required military service, he studied physics (the study of the relationship between matter and energy) at the University of Munich and at the University of Erlangen, receiving a doctorate from Erlangen in 1906 for his study of electrical releases through gases.

Work: Geiger was a pioneer in the field of nuclear physics. He started his research into equipment to count alpha particles in 1907, while as an assistant to Rutherford, the two developed an instrument to count individual charged particles in 1908

Other important work of Geiger was his investigation with E.Marsden in 1909 of the scattering of alpha particles by gold leafs, this lead Rutherford to propose his nuclear theory for the atom

The Geiger counter: Hans Geiger’s most famous invention is the Geiger counter .This primitive counter consisted of a gas filled tube with a wire at high voltage around the axis. A particle shot through the tube caused ionization as well as a discharge in the gas. Ionization is the process in which an ion is formed by the removal of a charged particle such as an electron. The pulse of the current that resulted from the particle was measured on a meter. Geiger and Rutherford discovered that alpha particles are doubly charged helium atoms. Later Geiger teamed up with W.Muller to refine the counter and make it more precise. The Geiger counter as we know it was completed in 1928.

The history of the counter: At Manchester university he began working under professor Earnest Rutherford. Together they did experiments in atomic physics. Rutherford was experimenting with radioactivity. For these experiments Geiger had to accurately measure the emanations from Radium. Then, in 1908, Geiger created the first Geiger counter.

Throughout the years he made improvements to the counter with Rutherford. He persuaded Rutherford to let Earnest Marsden help out in discovering Wide angled alpha scattering. This led the three to discover the existence of the atomic nucleus.

Use of the Counter: The counter was able to prove the compton effect because it could detect electrons, radiation quanta, neutrons and also gamma radiation, Later the counter was used by nuclear scientists as a highly accurate tool that could be used in sub-atomic studies and also in detection of radioactivity.

His Family Life: There is little know about Geiger’s personal life, most of the information available is about his scientific contributions and schooling. The only evidence of a family is a poor picture of a gravestone in which the names Hans and Isabeth(possibly his wife) were barely legible. There is also a little information about his father Wilhem Geiger, who studied remote and eastern cultures and languages. There is also a little information about his brother Rudolph who studied Meteorology and climatology.

His Death: Geiger was offered the chair of physics at the Technische Hochschule in 1936. He continued experimenting and improving the counter. He also became involved with politics after Adolf Hitler's (1889–1945) rise to power in Germany's National Socialist Party. He helped compose a position paper that was signed by seventy-five of Germany's most notable physicists. The paper was presented to Hitler's Education Ministry in late 1936. The document urged the government to keep its hands off science, complaining that there were too few new physicists and that students were avoiding the subject in Germany because of newspaper attacks on physics by National Socialists. Geiger continued working at the Technische Hochschule through World War II (1939–45; a war fought between the Axis powers—Germany, Italy, and Japan—and the Allied powers—Great Britain, France, the Soviet Union, and the United States), although he was often confined to bed with rheumatism. He had just started to show signs of improvement in his health when his home near Babelsberg, Germany, was occupied in June 1945. Geiger was forced to flee to Potsdam, Germany, where he died on September 24, 1945.

Hans Geiger

By- Upadhyay aditi-09E243 P.yaadha-09E252