Paul Peter Ewald

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Paul Peter Ewald (1934)

Paul Peter Ewald (born January 23, 1888 in Berlin , † August 22, 1985 in Ithaca , New York ) was a German physicist .

Life

Paul Ewald, the son of the historian and philologist Paul Ewald (1851-1887) and the painter Clara Ewald , née Philippson (1859-1948), did his doctorate at the University of Munich under Arnold Sommerfeld and habilitated in 1918 with a thesis on the crystal optics of X-rays .

In 1921 he became an associate professor at the Technical University of Stuttgart and in the same year turned down a position offered to him at the University of Münster . In 1928 he got his own small institute at the Technical University of Stuttgart, which worked closely with Richard Glocker's X-ray Institute . From 1932 to 1933 he was rector of the Technical University of Stuttgart.

In April 1933, Paul Peter Ewald resigned from this office because the National Socialists could not properly carry out his duties as rector. In 1938 he left Germany, as did his mother, who was subject to the restrictions of the Nuremberg Laws due to the Jewish descent of her father .

Paul Peter Ewald was the father-in-law of the Nobel laureate in physics, Hans Bethe . His daughter, Rose Ewald, met the physicist in 1937 at Duke University . Both married in September 1939.

In May 1991, the city of Stuttgart had a commemorative plaque attached to the building of the former X-ray Institute, Seestrasse 71, in honor of the physicist.

plant

Paul Peter Ewald was the first to provide the X-ray interference of the crystals with a theoretical basis and to make the details of the X-ray scattering experiments by Max von Laue (1911/12) understandable. Ewald founded the dynamic theory of X-ray interference, which can also be applied to other types of radiation ( electrons , neutrons , light ). Among other things, Ewald received the highest award from the German Physical Society , the Max Planck Medal .

The Ewald construction is used extensively today, the aim of which is to determine the possible diffraction directions of a primary X-ray beam when it hits a crystal. The core of Ewald's construction is the so-called Ewald sphere in the reciprocal point lattice (of the crystal), the points of which characterize sets of lattice planes in the crystal.

Awards

In 1932 he was elected a corresponding member of the Göttingen Academy of Sciences . In 1955 Ewald was elected to the American Academy of Arts and Sciences . In 1962, the Bavarian Academy of Sciences appointed him a corresponding member of the math and science class. In 1979 he became the first recipient of the Gregori Aminoff Prize . In 1966 he was elected a member of the Leopoldina .

Works (excerpt)

  • Crystals and X-rays (Springer, 1923)
  • The path of research (especially physics) (A. Bonz 'Erben (Stuttgart) 1932)
  • On the Foundations of Crystal Optics (Air Force Cambridge Research Laboratories, 1970)

Trivia

  • At DESY in Hamburg-Bahrenfeld, an experimental hall (building 46g) with the beamlines P64 and P65 of the PETRA ring is named after "Paul P. Ewald".

literature

  • Michael Eckert : Paul Peter Ewald (1888–1985) in National Socialist Germany: a study on the background of a scientist's emigration . In: Mark Walker and Dieter Hoffmann (eds.): “Foreign” scientists in the Third Reich. The Debye Affair in Context . Göttingen: Wallstein 2011, pp. 265–289.
  • Rainer Würgau: "Ewaldiana ". In: Communications of the German Society for Crystallography , Issue 44 (2014), pp. 71–81. (Full text of the issue) . About the Berlin scholar families Ewald and Philippson. PDF 4.7 MB, accessed July 2015.
  • Norbert Becker: Paul Peter Ewald . In: Norbert Becker / Katja Nagel: Persecution and disenfranchisement at the Technical University of Stuttgart during the Nazi era, Stuttgart: Belser 2017, pp. 227–232.

Web links

Commons : Paul Peter Ewald  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Wiliam J. Broad: Hans Bethe, Father of Nuclear Astrophysics, Dies at 98. The New York Times , March 7, 2005, accessed November 10, 2014 . (English)
  2. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 78.
  3. ↑ Dr. phil., Dr. rer. nat. hc Paul P. Ewald , members of the Bavarian Academy of Sciences
  4. ↑ Member entry of Paul Ewald at the German Academy of Natural Scientists Leopoldina , accessed on April 11, 2015.
  5. ^ PETRA III - Facility Information. Retrieved June 16, 2020 .
personal data
SURNAME Ewald, Paul Peter
BRIEF DESCRIPTION German physicist, crystallographer
DATE OF BIRTH January 23, 1888
PLACE OF BIRTH Berlin
DATE OF DEATH August 22, 1985
Place of death Ithaca , New York