Hans Georg Dehmelt (; 9 September 1922 – 7 March 2017) was a German and American physicist, who was awarded a

Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...

in 1989, for co-developing the

ion trap An ion trap is a combination of electric and/or magnetic fields used to capture charged particles — known as ions — often in a system isolated from an external environment. Atomic and molecular ion traps have a number of applications in phy ...

technique ( Penning trap) with Wolfgang Paul, for which they shared one-half of the prize (the other half of the Prize in that year was awarded to

Norman Foster Ramsey Norman Foster Ramsey Jr. (August 27, 1915 – November 4, 2011) was an American physicist who was awarded the 1989 Nobel Prize in Physics, for the invention of the separated oscillatory field method (see Ramsey Interferometry) which had importan ...

). Their technique was used for high precision measurement of the

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have n ...

magnetic moment In electromagnetism, the magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include loops of electric current (such as electroma ...

Biography

At the age of ten Dehmelt enrolled in the Berlinisches Gymnasium zum Grauen Kloster, a

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

school in

Berlin Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitu ...

, where he was admitted on a scholarship. After graduating in 1940, he volunteered for service in the

German Army The German Army (, "army") is the land component of the armed forces of Germany. The present-day German Army was founded in 1955 as part of the newly formed West German ''Bundeswehr'' together with the ''Marine'' (German Navy) and the ''Luftwaf ...

, which ordered him to attend the

University of Breslau A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...

to study physics in 1943. After a year of study he returned to army service and was captured during the

Battle of the Bulge The Battle of the Bulge, also known as the Ardennes Offensive, was the last major German offensive campaign on the Western Front during World War II. The battle lasted from 16 December 1944 to 28 January 1945, towards the end of the war in ...

. After his release from an American prisoner of war camp in 1946, Dehmelt returned to his study of physics at the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen, (german: Georg-August-Universität Göttingen, known informally as Georgia Augusta) is a public research university in the city of Göttingen, Germany. Founded ...

, where he supported himself by repairing and bartering old, pre-war radio sets. He completed his master's thesis in 1948 and received his PhD in 1950, both from the University of Göttingen. He was then invited to

Duke University Duke University is a private research university in Durham, North Carolina. Founded by Methodists and Quakers in the present-day city of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco and electric power industrialist Jam ...

as a postdoctoral associate, emigrating in 1952. Dehmelt became an assistant professor at the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seatt ...

Seattle, Washington Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest region ...

in 1955, an associate professor in 1958, and a full professor in 1961. In 1955 he built his first electron impact tube in George Volkoff's laboratory at the

University of British Columbia The University of British Columbia (UBC) is a public research university with campuses near Vancouver and in Kelowna, British Columbia. Established in 1908, it is British Columbia's oldest university. The university ranks among the top thr ...

and experimented on paramagnetic resonances in polarized atoms and free electrons. In the 1960s, Dehmelt and his students worked on spectroscopy of hydrogen and helium ions. The electron was finally isolated in 1973 with David Wineland, who continued work on trapped ions at NIST. He created the first geonium atom in 1976, which he then used to measure precise magnetic moments of the electron and positron with R. S. Van Dyck into the 1980s, work that led to his Nobel prize. In 1979 Dehmelt led a team that took the first photo of a single atom. He continued work on

s at the

, until his retirement in October 2002. In May 2010, he was honoured as one of Washington's Nobel laureates by

Crown Princess Victoria of Sweden Victoria, Crown Princess of Sweden, Duchess of Västergötland (Victoria Ingrid Alice Désirée; born 14 July 1977) is the heir apparent to the Swedish throne, as the eldest child of King Carl XVI Gustaf. If she ascends to the throne as expecte ...

at a special event in Seattle. He was married to Irmgard Lassow, now deceased, and the couple had a son, Gerd, also deceased. In 1989 Dehmelt married Diana Dundore, a physician. Dehmelt died on March 7, 2017 in Seattle, Washington, aged 94.

Awards and honors

* Davisson-Germer Prize in 1970. *

Rumford Prize Founded in 1796, the Rumford Prize, awarded by the American Academy of Arts and Sciences, is one of the oldest scientific prizes in the United States. The prize recognizes contributions by scientists to the fields of heat and light. These terms ...

in 1985. *

in 1989. *Golden Plate Award of the

American Academy of Achievement The American Academy of Achievement, colloquially known as the Academy of Achievement, is a non-profit educational organization that recognizes some of the highest achieving individuals in diverse fields and gives them the opportunity to meet ...

in 1990. *

National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social scienc ...

in 1995.

References

Sources *"Moby Electron" article by David H. Freeman, ''Discover Magazine'', February, 1991, pp. 51–56

External links

* including the Nobel Lecture, December 8, 1989 ''Experiments with an Isolated Subatomic Particle at Rest''
University of Washington home pageSeattle Times newspaper articleD. J. Wineland, "Hans G. Dehmelt", Biographical Memoirs of the National Academy of Sciences (2018)
{{DEFAULTSORT:Dehmelt, Hans Georg 1922 births 2017 deaths People from Görlitz American Nobel laureates American physicists Members of the United States National Academy of Sciences Fellows of the American Physical Society Silesian emigrants to the United States German Nobel laureates National Medal of Science laureates Nobel laureates in Physics People from the Province of Lower Silesia Duke University faculty University of Göttingen alumni University of Washington faculty University of Breslau alumni German prisoners of war in World War II held by the United States Mass spectrometrists German Army personnel of World War II