Karl-Ludwig Kratz

Karl -Ludwig Kratz ( born April 23, 1941 in Jena ) is a German nuclear chemist and astrophysicist. He is a professor of nuclear chemistry at the Johannes Gutenberg University in Mainz and an Adjunct Professor of Physics at the University of Notre Dame in South Bend, Indiana.

Nuclear Chemistry

He is the eldest son of the chemist Ludwig Kratz, who belonged to the train of 41 glassmaker Schott in Jena, which were spent in 1945 by the U.S. forces to West Germany. Accordingly, he spent his school years in Landshut and then in Mainz. He studied chemistry at the Johannes Gutenberg University in Mainz. At founded by Fritz Strassmann Institute of Nuclear Chemistry he obtained his doctorate in 1972 under the guidance of Günter Herrmann on the properties of neutron-rich isotopes halogen. These rapid and highly selective radiochemical separation methods for very short-lived, neutron- rich nuclei from the fission of uranium -235 were developed with thermal neutrons from the TRIGA MARK / II research neutron source of the institute. The problem of separation of often only small amounts of the investigated nuclide from the fission product mixture should scratch employ throughout his life as a researcher. These separation processes were decay properties of neutron-rich nuclides such as half-life and the emission probability for β - delayed neutrons ( a decay which ia occurs only in nuclei with high neutron excess ) was determined.

Karl -Ludwig Kratz developed methods to measure the energy of delayed neutrons. Together with the spectroscopic characteristic of both the emitted gamma radiation the core structure of short-lived fission products could be determined. These data of neutron-rich cores are used, for example, application in the reactor technology ( in particular, the data delayed neutrons are important for the control of the reactor ) and the nuclear synthesis (see below).

With the knowledge of each nuclide characteristic gamma radiation, the contents of ( trace ) elements in samples with leave of instrumental neutron activation analysis to determine a method that Karl- Ludwig Kratz applies his research group in environmental analysis and geochemistry.

Experiments on nuclear structure are now mainly carried out by international collaborations to mostly across countries operated research facilities. Scratch is a long time with his group at research reactors and accelerators such as the high-flux reactor of the Institute Laue -Langevin in Grenoble, the ISOLDE separator at the European Nuclear Research CERN in Geneva, the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, the National Superconducting Cyclotron Laboratory NSCL at the Michigan State University in East Lansing, Michigan, and other more nationally operated devices operate.

Nuclear Astrophysics

The experimental data of short-lived neutron- rich nuclides are introduced from scratch in nuclear astrophysics. Its territory is the nucleosynthesis, the structure of the elements from the ashes of the Big Bang in stars. Short-lived, extremely neutron rich nuclei occur in the so-called r-process (r = rapid, Eng. Quickly ) on, which is short-term result occurring high neutron fluxes during a stellar explosion ( supernova of type II) that of medium heavy nuclei in the iron group by alternating neutron capture - and β -decay processes to heavy elements up to uranium and thorium are synthesized. Frequency maxima in the distribution of elements in the solar system, the kosmochemisch from primitive meteorites ( carbonaceous chondrites ) were determined, can be explained by the influence of the core structure, in particular magic neutron numbers. The work Karl -Ludwig Kratzs ( in close cooperation with Friedrich -Karl Thielemann, University of Basel) gave evidence that the core structure in nuclei with high neutron excess of those of nuclei near the valley of β - stability, which are the study in laboratories on Earth accessible differs. The comparison of the calculated abundances of the elements seen in the observations of old stars with extremely low metallicity in the halo of the Milky Way ( as CS22892 -052, CS31082 - 001 or BD 17 ° 3248 ) makes it possible to determine the age of these stars that already a few hundred were formed millions of years after the Big Bang.

Leisure

In the spare time, scratch operated in the summer like a sailor and in winter alpine skiers. He is often able to combine work and leisure sports. Worth mentioning the regattas at conferences around the Masurian Lakes and the optimal combination of fully automated data acquisition in experiments at the Institut Laue -Langevin, Grenoble, departing runs in the nearby winter sports resorts of Chamrousse.

In March 2003, he launched a series of workshops on Nuclear Astrophysics in the Salzburger community Russbach am Pass Gschuett. Under the launched by the Helmholtz Association of German large-scale research facilities Virtual Institute of the structure of nuclei and nuclear astrophysics - VISTARS these meetings are students and experienced researchers and teachers together lead to contact, in the lecture hall and the ski slopes.

Honors

1999 awarded him (as only a few non- Americans ), the American Chemical Society, the Glenn T. Seaborg Award for Nuclear Chemistry, which his doctor father Günter Herrmann had received in 1988. 2004, GSI Exotic Nuclei Community awarded him their GENCO Award. On the occasion of his 65th birthday his associates him have the sponsorship of the star BD 17 ° 3248 when Karl -Ludwig Kratzs plotted star. In 2014 he was honored by the American Physical Society with the Hans A. Bethe - Prize.

Writings

  • Karl -Ludwig Kratz: decay properties of short-lived neutron-rich isotopes and halogen their yields in the fission of uranium -235 with thermal neutrons. Univ. Mainz, 1972 ( dissertation).
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