Charles Christian Lauritsen (April 4, 1892 – April 13, 1968) was a Danish/American
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 ...
.
Early life and career
Lauritsen was born in
Holstebro, Denmark
Holstebro is the main town in Holstebro Municipality, Denmark. The town, bisected by Storå, Denmark, ''Storåen'' ("The Large Creek") and has a population of 36,489 (1 January 2022).[United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...]
with his wife Sigrid Henriksen and son Tommy, first to Florida, where the family lived for a time on a houseboat, and later to Boston, where he worked as a draftsman during the
Great War
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
and was a witness to the
Boston Molasses Disaster
The Great Molasses Flood, also known as the Boston Molasses Disaster, was a disaster that occurred on January 15, 1919, in the North End neighborhood of Boston, Massachusetts.
A large storage tank filled with of molasses, weighing approximat ...
. By 1921 he was working in
Palo Alto
Palo Alto (; Spanish for "tall stick") is a charter city in the northwestern corner of Santa Clara County, California, United States, in the San Francisco Bay Area, named after a coastal redwood tree known as El Palo Alto.
The city was estab ...
on radio for communicating between ship and shore. He became interested in the design of
radio receiver
In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. Th ...
s, and for a few months in 1922 was in business with two partners building radios. By 1923 he had moved to
St. Louis
St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...
where he was chief engineer at the Kennedy Corporation, a producer of consumer radio receivers.
In 1926 Lauritsen attended a public lecture by
Robert Millikan
Robert Andrews Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric e ...
who, in casual conversation afterwards, invited him to visit
Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
. Lauritsen and his family soon moved to
Pasadena
Pasadena ( ) is a city in Los Angeles County, California, northeast of downtown Los Angeles. It is the most populous city and the primary cultural center of the San Gabriel Valley. Old Pasadena is the city's original commercial district.
Its ...
where he talked his way into graduate study in physics. In 1929 he received his
Ph.D.
A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is a ...
, and in 1930 he joined the physics department faculty. He spent the remainder of his academic career as Professor of Physics at this institution, finally retiring in 1962.
In 1928 he and Ralph D. Bennett developed
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
tubes of exceptionally high voltage. These tubes were then used for radiation therapy of
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
patients in the Kellogg Radiation Laboratory, built as a treatment clinic in 1931. Sigrid Lauritsen, who was one of the first female graduates of the
University of Southern California
The University of Southern California (USC, SC, or Southern Cal) is a Private university, private research university in Los Angeles, California, United States. Founded in 1880 by Robert M. Widney, it is the oldest private research university in C ...
medical school, worked in the clinic as a radiologist. In 1932 Lauritsen converted one of his X-ray tubes into an accelerator of protons and helium ions and began to study nuclear reactions. In 1934, Lauritsen and H. Richard Crane used a sample of recently discovered
deuterium
Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen (the other being Hydrogen atom, protium, or hydrogen-1). The atomic nucleus, nucleus of a deuterium ato ...
, obtained from G.N. Lewis at Berkeley, to generate
neutron
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
s with which they made the first accelerator-produced artificial radioactivity. He later measured the radiation produced when a
positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. It has an electric charge of +1 '' e'', a spin of 1/2 (the same as the electron), and the same mass as an electron. When a positron collides ...
and an
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 no kn ...
annihilate each other. One of his most significant discoveries was to show that protons could be captured by a
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
, releasing
gamma ray
A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
s. This radiative capture process was applied to the study of the nuclear processes at the heart of a
star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
, and the production of the heavier elements. In 1939 the laboratory ceased to do medical therapy and concentrated on nuclear physics. (Lauritsen was director of the laboratory from its inception until he retired in 1962.)
In 1937 he invented a radiation detector called the Lauritsen electroscope, widely used as
quartz fiber radiation dosimeter
A quartz fiber dosimeter, sometimes called a self indicating pocket dosimeter (SIPD) or self reading pocket dosimeter (SRPD) or quartz fibre electrometer (QFE), is a type of radiation dosimeter, a pen-like device that measures the cumulativ ...
s.
Weapons development
In 1940, more than a year before the U.S. entered
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 ...
, Lauritsen began work on weapons and weapons design. His initial work was on the design and development of the proximity fuze, but for most of the war he ran a large program at Caltech that developed and manufactured a variety of rocket weapons, mostly for the Navy. In this connection he helped found the Naval Ordnance Test Station (now The Naval Air Warfare Center, Weapons Division, China Lake, with a laboratory bearing his name) at
Inyokern, California
Inyokern (formerly Siding 16 and Magnolia) is a census-designated place (CDP) in Kern County, California, United States. Its name derives from its location near the border between Inyo and Kern Counties. Inyokern is located west of Ridgecrest, a ...
. In the last months of the war, he helped in the American efforts to design and build 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 ...
, including development of the "
pumpkin bomb
Pumpkin bombs were conventional aerial bombs developed by the Manhattan Project and used by the United States Army Air Forces against Japan during World War II. It was a close replication of the Fat Man plutonium bomb with the same ballistic an ...
", a high explosive copy of the
Fat Man
"Fat Man" (also known as Mark III) is the codename for the type of nuclear bomb the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the fir ...
bomb.
He continued his weapons work in the years following the war, and much of his work was classified. Among the projects in which he participated were
Project Hartwell
A project is any undertaking, carried out individually or collaboratively and possibly involving research or design, that is carefully planned to achieve a particular goal.
An alternative view sees a project managerially as a sequence of even ...
,
Project Charles Project Charles was a summer study group held at Massachusetts Institute of Technology (MIT), of which F.W. Loomis was the appointed head.
An agreement was formed between U.S. General Gordon Saville, Louis Ridenour, Ivan Getting and John McCone ...
, Project Michael, and
Project Vista
Project Vista was a top secret study conducted by prominent physicists, researchers, military officers, and staff at California Institute of Technology from April 1 to December 1, 1951. The project got its name from the Vista del Arroyo Hotel i ...
. During the
Korean War
, date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...
he was at the front lines just after the
Inchon landing
The Battle of Incheon (), also spelled Battle of Inchon, was an amphibious invasion and a battle of the Korean War that resulted in a decisive victory and strategic reversal in favor of the United Nations Command (UN). The operation involved s ...
s observing and evaluating American weaponry for the Defense Department. He served as an adviser to the U.S. government and as a member of many committees and other groups.
After a lengthy struggle with cancer, he died on April 13, 1968.
Awards and honors
* Elected to the Royal Danish Academy of Sciences and Letters, 1939.
* Appointed ''Commander'' of the
Order of Dannebrog
The Order of the Dannebrog ( da, Dannebrogordenen) is a Danish order of chivalry instituted in 1671 by Christian V. Until 1808, membership in the order was limited to fifty members of noble or royal rank, who formed a single class known a ...
, 1953, by the
King of Denmark
The monarchy of Denmark is a constitutional political system, institution and a historic office of the Kingdom of Denmark. The Kingdom includes Denmark proper and the autonomous administrative division, autonomous territories of the Faroe ...
.
* President of the
American Physical Society
The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of k ...
, 1951.
* Awarded the Tom W. Bonner Prize, 1967.
* Awarded an honorary Doctor of Laws degree by
UCLA
The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...
, 1965.
* The crater
Lauritsen on the
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
is named after him.
* Awarded the
Medal for Merit
The Medal for Merit was, during the period it was awarded, the highest civilian decoration of the United States. It was awarded by the President of the United States to civilians who "distinguished themselves by exceptionally meritorious conduct i ...
by President
Harry_S._Truman
Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. A leader of the Democratic Party, he previously served as the 34th vice president from January to April 1945 under Franklin ...
in 1948.
References
* William A. Fowler, "Charles Christian Lauritsen", 1969.
* Charles H. Holbrow, "Charles C. Lauritsen: A Reasonable Man in an Unreasonable World", ''Physics in Perspective'', vol. 5, 419-472, 2003.
* Knud Jakobsen, "Danskeren bag bomben" 2013 (in Danish)
External links
Guide to the Papers of Charles Christian Lauritsen, 1927-1977including his biography.
Target Committee, Los Alamos, May 10-11, 1945National Academy of Sciences Biographical Memoir
{{DEFAULTSORT:Lauritsen, Charles Christian
1892 births
1968 deaths
20th-century American physicists
American nuclear physicists
Manhattan Project people
Danish emigrants to the United States
United States Army Science Board people
People from Holstebro
Presidents of the American Physical Society