Luis Walter Alvarez

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Luis Alvarez (photo on his Los Alamos ID card during World War II)

Luis Walter Alvarez (born June 13, 1911 in San Francisco , California , † September 1, 1988 in Berkeley , California) was an American physicist , inventor and Nobel Prize winner .

Life

He was the son of a doctor Walter Alvarez (1884–1978) known throughout the USA through his columns as "America's Family Doctor", who was then working in medical research at the University of San Francisco . His grandfather came from Spain, but emigrated to the USA via Cuba, where he got rich from real estate in Los Angeles. His mother came from an Irish missionary family in China.

The family moved from San Francisco to Rochester, Minnesota, where his father worked at the Mayo Clinic . He studied from 1928 at the University of Chicago , where he made his diploma (master's) in 1934 and his doctorate in 1936 with Arthur Compton with a thesis on diffraction grating. For most of his career he was a professor at the University of Berkeley in California, where he worked with Ernest Lawrence immediately after receiving his doctorate in 1936, becoming an assistant professor in 1938 and a professor in 1945. In 1978 he retired. In 1988 he died of cancer.

During the Second World War, he worked at MIT's Radiation Laboratory from 1940 to 1943 , from 1943 in the Metallurgical Laboratory in Chicago as a member of the Manhattan Project and from 1944 in Los Alamos. From 1954 to 1959 he was Associate Director of the Radiation Laboratory at Berkeley University and from 1976 to 1978 Associate Director of the Lawrence Berkeley National Laboratory .

Alvarez was an avid private aviator and golfer. He had been married to Geraldine Smithwick since 1936 and had two children, Walter and Jean. The marriage fell apart during the long periods of separation in times of war. He was married to Janet Landis since 1958 and had two other children, Donald and Helen.

In 1938 he became a Fellow of the American Physical Society . He was a member of the National Academy of Sciences since 1947 , of the American Philosophical Society since 1953, and of the American Academy of Arts and Sciences since 1958 . In 1963 he received the National Medal of Science and in 1987 the Enrico Fermi Prize . In 1973 he was on the Science Advisory Committee of the US President. In 1969 he was President of the American Physical Society.

Frank Crawford is one of his PhD students .

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As a student, he and others discovered the “east-west effect” in cosmic rays . The different intensity depending on the direction of the compass indicates a proportion of positively charged particles in this radiation. In 1937 he was able to demonstrate the so-called electron capture for the first time , which Hideki Yukawa had predicted in 1935 . In 1939 he and Felix Bloch determined the magnetic moment of the neutron , for which they had to generate a beam of slow neutrons. Also in 1939 he discovered the hydrogen isotope tritium , predicted by Mark Oliphant in 1934 , which was later important for fusion.

Luis Alvarez in front of the B-29 bomber " The Great Artiste "

During the Second World War he worked on the development of the atomic bomb and radar . At the MIT "Radiation Lab", where he began his work for the military in 1940, he developed three radar systems. One for a safe landing system for aircraft in poor visibility (GCA, Ground Controlled Approach ), for which a radar with a narrow beam (narrow beam radar) had to be developed. Another (called an Eagle) was used to locate and bomb objects on the ground from the aircraft, a third was used for air defense or air surveillance (microwave early warning system). In the Manhattan Project , on which he worked from 1943, he developed the electrical ignition mechanism for the plutonium bombs and was a member of the scientific delegation that investigated the effects in Hiroshima and Nagasaki, including being a scientific observer on board the B-29 bomber " The Great Artiste ” , who accompanied the “ Enola Gay ” when it was dropped on Hiroshima . Alvarez was dismayed by the effects, but advocated the use of the bombs to shorten the war.

After the war he developed the proton linear accelerator in Berkeley , which was in use from 1947. He was also co-developer of the first synchrotron in Berkeley . From 1950 he turned to detector development.

Alvarez received the 1968 Nobel Prize in Physics "for his decisive contribution to elementary particle physics , in particular his discovery of a large number of resonance states , made possible by his development of techniques for the hydrogen bubble chamber and in data analysis". Alvarez improved Donald Glaser's bubble chamber (liquid hydrogen instead of ether, building ever larger and more sophisticated chambers) and was primarily responsible for the development of fast data acquisition electronics, which made the discovery of these very short-lived particles possible in the first place. He developed delay mechanisms for the electronic impulses and computer programs for filtering out the significant events. In the course of this research he discovered the Omega meson in 1961 , which was important for confirming the Quark model.

Luis Alvarez, Ahmed Fakhry and Jerry Anderson with the equipment for the pyramid project

1965–1969, Alvarez tried to find out with the help of measurements of cosmic radiation whether there were undiscovered chambers in the Chephren pyramid in Egypt. He measured the attenuation of the muons in a chamber below the pyramid depending on the direction of incidence and compared the data with a simulation. Alvarez claimed to have proven that there were no such chambers. However, French architects later found that the Alvarez method would have overlooked the main burial chambers of the Great Pyramid of Cheops as the granite used there almost offset the effects of the cavities in the limestone.

Alvarez assisted the Warren Commission to investigate the Kennedy assassination. He also analyzed the Zapruder film and came to the conclusion that the facts are compatible with Lee Harvey Oswald's sole responsibility (specifically, the head flung backwards).

Luis Alvarez and his son, the geologist Walter Alvarez , also proposed the theory that a meteorite impact was responsible for the mass extinction of the dinosaurs (see also: KT impact ). To do this, they measured the anomalously high proportion of iridium worldwide in the boundary layer from the Cretaceous to the Tertiary , which can only be explained by its extraterrestrial origin.

He is also the inventor of a variable focus thin lense, a color television system, and invented an "in door" electronic golf machine for President Dwight D. Eisenhower . Together with his student Jake Wiens, he developed a mercury vapor lamp, the wavelength of which was chosen as a length measure by the " National Bureau of Standards " in the USA. For his inventions (22 patents) he was inducted into the "National Inventors Hall of Fame" in 1978. In 1988 the asteroid (3581) Alvarez was named after him.

literature

Web links

Commons : Luis Walter Alvarez  - Collection of images, videos and audio files

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  1. ↑ Luis W. Alvarez, W. Peter Trower: Discovering Alvarez: selected works of Luis W. Alvarez, with commentary by his students and colleagues , University of Chicago Press, 1987, ISBN 0226813045 , p. 65
  2. ↑ Similar electronics were also necessary in the development of the atom bombs
  3. ↑ Lakshmanan, Montlucon 1987, quoted in Probing Pyramids to Identify Internal Structure ( Memento June 5, 2007 in the Internet Archive )
  4. ↑ Alvarez A physicist examines the Kennedy assassination movie , American Journal of Physics, Volume 44, 1976, 813
  5. ↑ Minor Planet Circ. 12807
personal data
SURNAME Alvarez, Luis Walter
BRIEF DESCRIPTION American physicist and Nobel Prize winner
DATE OF BIRTH June 13, 1911
PLACE OF BIRTH San Francisco , California
DATE OF DEATH September 1, 1988
Place of death Berkeley , California