Gerhard Dickel (28 October 1913 – 3 November 2017) was a German

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

and

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...

. He developed a thermal diffusion method of separating isotopes with

Klaus Clusius Klaus Paul Alfred Clusius (19 March 1903 – 28 May 1963) was a German physical chemist from Breslau (Wrocław), Silesia. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club; he worked on isotope ...

in 1938, sometimes referred to as Clusius-Dickel separation. Clusius-Dickel_separation_DMarshall2021

Biography

He was born in

Augsburg Augsburg (; bar , Augschburg , links=https://en.wikipedia.org/wiki/Swabian_German , label=Swabian German, , ) is a city in Swabia, Bavaria, Germany, around west of Bavarian capital Munich. It is a university town and regional seat of the ' ...

. He studied under Clusius at the Institute for Physical Chemistry of the

Ludwig Maximilian University of Munich The Ludwig Maximilian University of Munich (simply University of Munich or LMU; german: Ludwig-Maximilians-Universität München) is a public research university in Munich, Germany. It is Germany's sixth-oldest university in continuous operatio ...

. Clusius and Dickel published a paper in 1938 announcing that they had separated isotopes of

neon Neon is a chemical element with the symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypton ...

. They had discovered that the normally inefficient thermal diffusion method – where isotopes in a fluid diffuse towards opposing hotter and colder regions – could be improved by more than four orders of magnitude if there was also an optimal convection current between the regions to avoid a steady concentration gradient and "back diffusion" developing. In 1939, the year Dickel defended his PhD thesis, the pair announced that they had also separated isotopes of chlorine with the same process. It was explored on a large scale in the USA during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

as a possible method for separating

uranium-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exis ...

from the more abundant

uranium-238 Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it ...

in order to make an

atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb ...

(the more-efficient

gaseous diffusion Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride (UF6) through semipermeable membranes. This produces a slight separation between the molecules containing uranium-235 (235U) and uranium-2 ...

was eventually chosen). Dickel became a substitute manager of the Institute for Physical Chemistry, followed by a position as adjunct professor. In 1957, he became head of department at the university's Physics Institute. The same year he received the Bodenstein Prize from the German Bunsen Society for Physical Chemistry, for work on isotope exchange and on diffusion in gases and gels. He retired in 1978. He died in 2017, aged 104.

References

1913 births 2017 deaths Ludwig Maximilian University of Munich alumni 20th-century German chemists 21st-century German chemists 20th-century German physicists Scientists from Augsburg German centenarians Men centenarians {{Germany-chemist-stub