When Heinz Maier-Leibnitz, an emeritus professor of physics, received the ring of honor from his alma mater, the Technical University of Munich, I had the privilege of putting it on his finger at his home in Allensbach, Germany. He felt deeply honored. He died the next morning, 16 December 2000, of cancer.

Born on 28 March 1911 in Esslingen, Germany, Maier-Leibnitz studied physics at the universities of Stuttgart and Göttingen. As the last student of James Franck, Maier- Leibnitz earned a PhD degree in physics in 1935 from the University of Göttingen. The research was in the field of atomic physics, and Maier-Leibnitz discovered metastable, negative helium ions, which were later used for acceleration. Subsequently, he joined Walther Bothe in Heidelberg, where he improved the electron-gamma-ray coincidence technique, confirmed energy conservation in Compton scattering, and founded the field of nuclear spectroscopy.

At the beginning of World War II, Maier-Leibnitz served in the German air defense and later as a meteorologist at air bases in France. In 1942, he returned to Heidelberg to work with Bothe on decay schemes of radioactive nuclei using his coincidence technique.

After World War II, Maier-Leibnitz continued to work in nuclear spectroscopy and applied radioactive tracers in biochemistry and medicine. He also studied positron annihilation in solids, which became a new tool for measuring the momentum distribution of bound electrons. A measurement of the antineutrino angular distribution in the lithium-8 beta decay led to the discovery (in 1958) of the right-handedness of the antineutrino, shortly after the fall of parity.

In 1952, Maier-Leibnitz became professor of technical physics at the Technical University of Munich. He attracted many students to the field of nuclear physics, emphasizing research on new frontiers. One of his students, Rudolf Mössbauer, discovered recoil-free nuclear resonance fluorescence of gamma rays in solids, for which Mössbauer received the Nobel Prize in Physics in 1961. Maier-Leibnitz had created a school of innovative modern physics and received high international acclaim.

Maier-Leibnitz was offered the opportunity to build the first German research reactor in Garching, near Munich, in 1956. The 1-MW swimming-pool-type reactor was supported by the US government's Atoms for Peace Program. To make it competitive with other reactors, he decided to concentrate on simple yet innovative methods not used elsewhere to make precision experiments with his inexperienced students. He focused on neutron-capture spectroscopy, fission studies, and especially neutron optics. With a deep understanding of the index of refraction of neutrons in a medium, he invented neutron guide tubes, an interferometer, a refractometer, and a neutron turbine for the production of, and a neutron bottle for the storage of, ultracold neutrons. A novel high-resolution back-scattering spectrometer revolutionized inelastic neutron scattering.

Maier-Leibnitz was also one of the first to realize that the neutron flux of his reactor was too low for some interesting projects, so he urged the construction of a high-flux neutron source. In 1967, he finally succeeded with a French-German project and became the first director of the Institute Max von Laue-Paul Langevin (ILL) in Grenoble, France. The ILL reactor was tailored by Robert Dautray, a young French engineer and later the high commissioner of the CEA (French Atomic Energy Commission), to the requirements of the novel instrumentation developed by Maier-Leibnitz and his students in Munich. The reactor had the first source of cold neutrons and a large hall filled with many neutron guides for thermal and cold neutrons in a background-free environment.

Later, a neutron turbine for slowing down cold neutrons was added, providing ultracold neutrons for storage in totally reflecting material bottles and in a magnetic storage ring. This unique facility allows precision measurements of the neutron lifetime and a constantly decreasing limit for the electric dipole moment of the neutron. The reactor also has special beam tubes with internal targets for precision neutron-capture gamma-ray and conversion-electron spectroscopy, and for studies of the dynamics of the fission process. The ILL still is an El Dorado for high- resolution inelastic neutron scattering, diffracting small-angle scattering, and many other studies with polarized and unpolarized neutrons. Thanks to Maier-Leibnitz, the facility became a genuine users' laboratory, with free access to anyone who wanted to use neutrons for research.

Maier-Leibnitz held many offices. He was president of the International Union of Pure and Applied Physics from 1972 to 1975. From 1974 to 1979, he was president of the German Research Foundation. He received many honors in Germany and abroad, including the Otto Hahn Prize (1986) and the Stern-Gerlach Medal (1996) from the German Physical Society and the Austrian Medal of Science and Art (1985) from the Austrian Physical Society. He also was Chancellor of the Order for Merit and Officer of the Legion of Honor of the Republic of France.

During the discussion of his valedictory lecture in 1980, "How Does One Find Something New?" someone insisted that "luck" should be mentioned. Maier-Leibnitz refused, telling the following anecdote: "In 1937, I irradiated a water-soluble uranium salt in a cloud chamber with neutrons. Because it was dissolved by the vapor, I covered it with the thinnest mica foil I had, and considered myself as the world champion in mica splitting." But this world-class mica also stopped the fission products. "Was this bad luck? No, it was my ignorance of chemistry," was the assessment of Maier-Leibnitz.

Maier-Leibnitz put all his effort unselfishly into the education of his students by creating a successful school of experimental physics. We have lost a great scientist who also was sincerely humane and loved nature. This generation is very grateful to this eminent scientist, teacher, and warm-hearted person.

© 2001 American Institute of Physics