Johannes Wilhelm "Hans" Geiger (/ˈɡaɪɡər/; German: [ˈɡaɪɡɐ]; 30 September 1882 – 24 September 1945) was a German physicist. He is 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. He was the brother of meteorologist and climatologist Rudolf Geiger.
Hans Wilhelm Geiger (1928)
|Born||30 September 1882|
|Died||24 September 1945 (aged 62)|
|Known for||Geiger counter|
|Awards||Hughes Medal (1929)|
Duddell Medal and Prize (1937)
|Fields||Physics and sciences|
|Institutions||University of Erlangen|
University of Manchester
John Mitchell Nuttall
Geiger was born at Neustadt an der Haardt, Germany. 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 the University of Erlangen and was awarded a doctorate in 1906. His thesis was on electrical discharges through gases. 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 and led to Rutherford's winning the 1908 Nobel Prize in Chemistry.
In 1912, Geiger was named head radiation research at the German National Institute of Science and Technology in Berlin. 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). Work was interrupted when Geiger served in the German military during World War I as an artillery officer from 1914 to 1918.
In 1925, he began a teaching position at the University of Kiel where, in 1928 Geiger and his student Walther Müller created an improved version of the Geiger tube, the Geiger–Müller tube. This new device not only detected alpha particles, but beta and gamma particles as well, and is the basis for the Geiger counter.
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 the Technische Universität Berlin (Technical University of 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 atomic 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 it was incorrectly determined that nuclear weapons would not play a major 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.
Geiger endured the investiture of Berlin and subsequent Russian occupation (April/May 1945). Two months later he moved to Potsdam, dying there two months after the first nuclear bomb exploded over Japan.
Events in the year 1882 in Germany.1882 in science
The year 1882 in science and technology involved some significant events, listed below.1914–15 SK Rapid Wien season
The 1914-15 SK Rapid Wien season was the 17th season in club history.1920–21 SK Rapid Wien season
The 1920-21 SK Rapid Wien season was the 23rd season in club history.Campbell's theorem (probability)
In probability theory and statistics, Campbell's theorem or the Campbell–Hardy theorem is either a particular equation or set of results relating to the expectation of a function summed over a point process to an integral involving the mean measure of the point process, which allows for the calculation of expected value and variance of the random sum. One version of the theorem, also known as Campbell's formula, entails an integral equation for the aforementioned sum over a general point process, and not necessarily a Poisson point process. There also exist equations involving moment measures and factorial moment measures that are considered versions of Campbell's formula. All these results are employed in probability and statistics with a particular importance in the theory of point processes and queueing theory as well as the related fields stochastic geometry, continuum percolation theory, and spatial statistics.Another result by the name of Campbell's theorem is specifically for the Poisson point process and gives a method for calculating moments as well as the Laplace functional of a Poisson point process.
The name of both theorems stems from the work by Norman R. Campbell on thermionic noise, also known as shot noise, in vacuum tubes, which was partly inspired by the work of Ernest Rutherford and Hans Geiger on alpha particle detection, where the Poisson point process arose as a solution to a family of differential equations by Harry Bateman. In Campbell's work, he presents the moments and generating functions of the random sum of a Poisson process on the real line, but remarks that the main mathematical argument was due to G. H. Hardy, which has inspired the result to be sometimes called the Campbell–Hardy theorem.Ernest Rutherford
Ernest Rutherford, 1st Baron Rutherford of Nelson, HFRSE LLD (30 August 1871 – 19 October 1937), was a New Zealand physicist who came to be known as the father of nuclear physics. Encyclopædia Britannica considers him to be the greatest experimentalist since Michael Faraday (1791–1867).In early work, Rutherford discovered the concept of radioactive half-life, the radioactive element radon, and differentiated and named alpha and beta radiation. This work was performed at McGill University in Canada. It is the basis for the Nobel Prize in Chemistry he was awarded in 1908 "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances", for which he was the first Canadian and Oceanian Nobel laureate.
Rutherford moved in 1907 to the Victoria University of Manchester (today University of Manchester) in the UK, where he and Thomas Royds proved that alpha radiation is helium nuclei. Rutherford performed his most famous work after he became a Nobel laureate. In 1911, although he could not prove that it was positive or negative,
he theorized that atoms have their charge concentrated in a very small nucleus,
and thereby pioneered the Rutherford model of the atom, through his discovery and interpretation of Rutherford scattering by the gold foil experiment of Hans Geiger and Ernest Marsden. He conducted research that led to the first "splitting" of the atom in 1917 in a nuclear reaction between nitrogen and alpha particles, in which he also discovered (and named) the proton.Rutherford became Director of the Cavendish Laboratory at the University of Cambridge in 1919. Under his leadership the neutron was discovered by James Chadwick in 1932 and in the same year the first experiment to split the nucleus in a fully controlled manner was performed by students working under his direction, John Cockcroft and Ernest Walton. After his death in 1937, he was honoured by being interred with the greatest scientists of the United Kingdom, near Sir Isaac Newton's tomb in Westminster Abbey. The chemical element rutherfordium (element 104) was named after him in 1997.Geiger (surname)
Geiger is a German or French surname. In the German language Geiger means "violin player."Geiger counter
A Geiger counter is an instrument used for detecting and measuring ionizing radiation. Also known as a Geiger–Mueller counter (or Geiger–Müller counter), it is widely used in applications such as radiation dosimetry, radiological protection, experimental physics, and the nuclear industry.
It detects ionizing radiation such as alpha particles, beta particles, and gamma rays using the ionization effect produced in a Geiger–Müller tube, which gives its name to the instrument. In wide and prominent use as a hand-held radiation survey instrument, it is perhaps one of the world's best-known radiation detection instruments.
The original detection principle was realized in 1908, at the Victoria University of Manchester, but it was not until the development of the Geiger–Müller tube in 1928 that the Geiger counter could be produced as a practical instrument. Since then, it has been very popular due to its robust sensing element and relatively low cost. However, there are limitations in measuring high radiation rates and the energy of incident radiation.Geiger–Marsden experiment
The Geiger–Marsden experiments (also called the Rutherford gold foil experiment) were a landmark series of experiments by which scientists discovered that every atom contains a nucleus where all of its positive charge and most of its mass are concentrated. They deduced this by measuring how an alpha particle beam is scattered when it strikes a thin metal foil. The experiments were performed between 1908 and 1913 by Hans Geiger and Ernest Marsden under the direction of Ernest Rutherford at the Physical Laboratories of the University of Manchester.Geiger–Müller tube
The Geiger–Müller tube or G–M tube is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation. It was named after Hans Geiger, who invented the principle in 1908, and Walther Müller, who collaborated with Geiger in developing the technique further in 1928 to produce a practical tube that could detect a number of different radiation types.It is a gaseous ionization detector and uses the Townsend avalanche phenomenon to produce an easily detectable electronic pulse from as little as a single ionising event due to a radiation particle. It is used for the detection of gamma radiation, X-rays, and alpha and beta particles. It can also be adapted to detect neutrons. The tube operates in the "Geiger" region of ion pair generation. This is shown on the accompanying plot for gaseous detectors showing ion current against applied voltage.
While it is a robust and inexpensive detector, the G–M is unable to measure high radiation rates efficiently, has a finite life in high radiation areas and cannot measure incident radiation energy, so no spectral information can be generated and there is no discrimination between radiation types; such as between alpha and beta particles.Geiger–Nuttall law
In nuclear physics, the Geiger–Nuttall law or Geiger–Nuttall rule relates the decay constant of a radioactive isotope with the energy of the alpha particles emitted. Roughly speaking, it states that short-lived isotopes emit more energetic alpha particles than long-lived ones.
The relationship also shows that half-lives are exponentially dependent on decay energy, so that very large changes in half-life make comparatively small differences in decay energy, and thus alpha particle energy. In practice, this means that alpha particles from all alpha-emitting isotopes across many orders of magnitude of difference in half-life, all nevertheless have about the same decay energy.
Formulated in 1911 by Hans Geiger and John Mitchell Nuttall, in its modern form the Geiger–Nuttall law is
where λ is the decay constant (λ = ln2/half-life), Z the atomic number, E the total kinetic energy (of the alpha particle and the daughter nucleus), and a1 and a2 are constants. The law works best for nuclei with even atomic number and even atomic mass. The trend is still there for even-odd, odd-even, and odd-odd nuclei but not as pronounced.Hans Geiger (footballer)
Hans Geiger (born 24 December 1905; died 17 December 1974) was a German international footballer.John Mitchell Nuttall
John Mitchell Nuttall (21 July 1890 – 28 January 1958) was an English physicist, born in Todmorden. He is best remembered for his work with the physicist Hans Geiger, which resulted in the Geiger–Nuttall law of radioactive decay.
Nuttall graduated from the University of Manchester in 1911 and was appointed Assistant Lecturer in Physics at the University of Leeds. During World War I, he served as a captain with the Royal Engineers. In 1921 he became Assistant Director of the University of Manchester's Physical Laboratories, a post he held until 1955.Kernphysikalische Forschungsberichte
Kernphysikalische Forschungsberichte (Research Reports in Nuclear Physics) was an internal publication of the German Uranverein, which was initiated under the Heereswaffenamt (Army Ordnance Office) in 1939; in 1942, supervision of the Uranverein was turned over to the Reichsforschungsrat under the Reichserziehungsministerium. Reports in this publication were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. Many of the reports are available at the Karlsruhe Nuclear Research Center and the Niels Bohr Library of the American Institute of Physics. Many of them are reprinted and transcribed in the book
"Collected Works / Gesammelte Werke" listed below which is available in most libraries. There are reports numbered G-1 to G-395.Prominent German scientists who published reports in Kernphysikalische Forschungsberichte as members of the Uranverein can be grouped as follows:
Nine of the ten German nuclear physicists, except for Max von Laue, incarcerated in England at the close of World War II under Operation Epsilon: Erich Bagge, Kurt Diebner, Walther Gerlach, Otto Hahn, Paul Harteck, Werner Heisenberg, Horst Korsching, Carl Friedrich von Weizsäcker, and Karl Wirtz.
German physicists sent to Russia to work on the Soviet atomic bomb project: Robert Döpel, Walter Herrmann, Heinz Pose, Nikolaus Riehl, and Karl Zimmer.
Others: Fritz Bopp, Walther Bothe, Wolfgang Finkelnburg, Siegfried Flügge, Hans Geiger, Karl-Heinz Höcker, Fritz Houtermans, Georg Joos, Horst Korsching, Carl Ramsauer, Fritz Sauter, and Fritz Strassmann.Otto Klemperer (physicist)
Otto Ernst Heinrich Klemperer (1899–1987) was a physicist expert in electron optics. He was granted his doctorate by the Humboldt-Universität zu Berlin in 1923. His thesis advisor was Hans Geiger. He continued to work with Geiger in the 1930s.Klemperer was co-inventor in 1928 of the Geiger-Klemperer ball counter, "the first major advance in the design of proportional counters". During the 1930s, he worked at the Cavendish Laboratory at the University of Cambridge on discrepancies between Fermi's theory of β-decay and the observed radiation properties of rubidium and polonium. He was later an Assistant Professor and Reader in Physics at Imperial College, London, where he wrote the third edition of his book on electron optics with Mike Barnett.The conductor Otto Klemperer was his father's cousin.
His uncle was the Romanist Victor KlempererRutherford scattering
Rutherford scattering is the elastic scattering of charged particles by the Coulomb interaction. It is a physical phenomenon explained by Ernest Rutherford in 1911 that led to the development of the planetary Rutherford model of the atom and eventually the Bohr model. Rutherford scattering was first referred to as Coulomb scattering because it relies only upon the static electric (Coulomb) potential, and the minimum distance between particles is set entirely by this potential. The classical Rutherford scattering process of alpha particles against gold nuclei is an example of "elastic scattering" because neither the alpha particles nor the gold nuclei are internally excited. The Rutherford formula (see below) further neglects the recoil kinetic energy of the massive target nucleus.
The initial discovery was made by Hans Geiger and Ernest Marsden in 1909 when they performed the gold foil experiment in collaboration with Rutherford, in which they fired a beam of alpha particles (helium nuclei) at foils of gold leaf only a few atoms thick. At the time of the experiment, the atom was thought to be analogous to a plum pudding (as proposed by J. J. Thomson), with the negatively-charged electrons (the plums) studded throughout a positive spherical matrix (the pudding). If the plum-pudding model were correct, the positive "pudding", being more spread out than in the correct model of a concentrated nucleus, would not be able to exert such large coulombic forces, and the alpha particles should only be deflected by small angles as they pass through.
However, the intriguing results showed that around 1 in 8000 alpha particles were deflected by very large angles (over 90°), while the rest passed through with little deflection. From this, Rutherford concluded that the majority of the mass was concentrated in a minute, positively-charged region (the nucleus) surrounded by electrons. When a (positive) alpha particle approached sufficiently close to the nucleus, it was repelled strongly enough to rebound at high angles. The small size of the nucleus explained the small number of alpha particles that were repelled in this way. Rutherford showed, using the method outlined below, that the size of the nucleus was less than about 10−14 m (how much less than this size, Rutherford could not tell from this experiment alone; see more below on this problem of lowest possible size). As a visual example, Figure 1 shows the deflection of an alpha particle by a nucleus in the gas of a cloud chamber.
Rutherford scattering is now exploited by the materials science community in an analytical technique called Rutherford backscattering.Timeline of particle physics technology
Timeline of particle physics technology
1896 - Charles Wilson discovers that energetic particles produce droplet tracks in supersaturated gases
1897-1901 - Discovery of the Townsend discharge by John Sealy Townsend
1908 - Hans Geiger and Ernest Rutherford use the Townsend discharge principle to detect alpha particles.
1911 - Charles Wilson finishes a sophisticated cloud chamber
1928 - Hans Geiger and Walther Muller invent the Geiger Muller tube, which is based upon the gas ionisation principle used by Geiger in 1908, but is a practical device that can also detect beta and gamma radiation. This is implicitly also the invention of the Geiger Muller counter.
1934 - Ernest Lawrence and Stan Livingston invent the cyclotron
1945 - Edwin McMillan devises a synchrotron
1952 - Donald Glaser develops the bubble chamber
1968 - Georges Charpak and Roger Bouclier build the first multiwire proportional mode particle detection chamberWalther Bothe
Walther Wilhelm Georg Bothe (8 January 1891 – 8 February 1957) was a German nuclear physicist, who shared the Nobel Prize in Physics in 1954 with Max Born.
In 1913, he joined the newly created Laboratory for Radioactivity at the Reich Physical and Technical Institute (PTR), where he remained until 1930, the latter few years as the director of the laboratory. He served in the military during World War I from 1914, and he was a prisoner of war of the Russians, returning to Germany in 1920. Upon his return to the laboratory, he developed and applied coincidence methods to the study of nuclear reactions, the Compton effect, cosmic rays, and the wave–particle duality of radiation, for which he would receive the Nobel Prize in Physics in 1954.
In 1930 he became a full professor and director of the physics department at the University of Giessen. In 1932, he became director of the Physical and Radiological Institute at the University of Heidelberg. He was driven out of this position by elements of the deutsche Physik movement. To preclude his emigration from Germany, he was appointed director of the Physics Institute of the Kaiser Wilhelm Institute for Medical Research (KWImF) in Heidelberg. There, he built the first operational cyclotron in Germany. Furthermore, he became a principal in the German nuclear energy project, also known as the Uranium Club, which was started in 1939 under the supervision of the Army Ordnance Office.
In 1946, in addition to his directorship of the Physics Institute at the KWImf, he was reinstated as a professor at the University of Heidelberg. From 1956 to 1957, he was a member of the Nuclear Physics Working Group in Germany.
In the year after Bothe's death, his Physics Institute at the KWImF was elevated to the status of a new institute under the Max Planck Society and it then became the Max Planck Institute for Nuclear Physics. Its main building was later named Bothe laboratory.Walther Müller
Walther Müller (6 September 1905 in Hanover – 4 December 1979 in Walnut Creek, California), was a German physicist, most well known for his improvement of Hans Geiger's counter for ionizing radiation, now known as the Geiger-Müller tube.
Walther Müller studied physics, chemistry and philosophy at the University of Kiel. In 1925 he became the first PhD student of Hans Geiger, who had just got a professorship in Kiel. Their work on ionization of gases by collision lead to the invention of the Geiger-Müller counter, a now indispensable tool for measuring radioactive radiation.
After some time as professor at the University of Tübingen he worked for the rest of his professional life as industrial physicist (i. e. a physicist working in industrial R&D) in Germany, then as an advisor for the Australian Postmaster-General's Department Research Laboratories in Melbourne, and then as an industrial physicist in the United States, where he also founded a company to manufacture Geiger–Müller tubes.