Robert Bacher
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Robert Fox Bacher (August 31, 1905November 18, 2004) was an American
nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics * Nuclear space *Nuclear ...
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 cau ...
and one of the leaders of the
Manhattan Project The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the ...
. Born in
Loudonville, Ohio Loudonville is a village in Ashland and Holmes counties in the U.S. state of Ohio. The population was 2,786 at the 2020 census. Loudonville is nicknamed the "Canoe Capital of Ohio" for the many canoe liveries along the Mohican River. It is al ...
, Bacher obtained his
undergraduate degree An undergraduate degree (also called first degree or simply degree) is a colloquial term for an academic degree earned by a person who has completed undergraduate courses. In the United States, it is usually offered at an institution of higher ed ...
and doctorate from the
University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...
, writing his 1930 doctoral thesis under the supervision of
Samuel Goudsmit Samuel Abraham Goudsmit (July 11, 1902 – December 4, 1978) was a Dutch-American physicist famous for jointly proposing the concept of electron spin with George Eugene Uhlenbeck in 1925. Life and career Goudsmit was born in The Hague, Ne ...
on the
Zeeman effect The Zeeman effect () is the splitting of a spectral line into several components in the presence of a static magnetic field. It is caused by the interaction of the magnetic field with the magnetic moment of the atomic electron associated with ...
of the
hyperfine structure In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate electronic energy levels and the resulting splittings in those electronic energy levels of atoms, molecules, and ions, due to electromagnetic multipole int ...
of atomic levels. After graduate work at the
California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...
(Caltech) and the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
(MIT), he accepted a job at
Columbia University Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...
. In 1935 he accepted an offer from
Hans Bethe Hans Albrecht Eduard Bethe (; ; July 2, 1906 – March 6, 2005) was a German-American physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics and solid-state physics, and received the Nobel Prize in Physi ...
to work with him at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
in
Ithaca, New York Ithaca () is a city in and the county seat of Tompkins County, New York, United States. Situated on the southern shore of Cayuga Lake in the Finger Lakes region of New York (state), New York, Ithaca is the largest community in the Ithaca metrop ...
. It was there that Bacher collaborated with Bethe on his book ''Nuclear Physics. A: Stationary States of Nuclei'' (1936), the first of three books that would become known as the "Bethe Bible". In December 1940, Bacher joined the
Radiation Laboratory The Radiation Laboratory, commonly called the Rad Lab, was a microwave and radar research laboratory located at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. It was first created in October 1940 and operated until 3 ...
at MIT, although he did not immediately cease his research at Cornell into the
neutron cross section In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm2 for which the number of ...
of
cadmium Cadmium is a chemical element; it has chemical symbol, symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Like z ...
. The Radiation Laboratory was organized into two sections, one for incoming
radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
signals, and one for outgoing radar signals. Bacher was appointed to handle the incoming signals section. Here he gained valuable experience in administration, coordinating not just the efforts of his scientists, but also those of
General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...
and
RCA RCA Corporation was a major American electronics company, which was founded in 1919 as the Radio Corporation of America. It was initially a patent pool, patent trust owned by General Electric (GE), Westinghouse Electric Corporation, Westinghou ...
. In 1942, Bacher was approached by
Robert Oppenheimer J. Robert Oppenheimer (born Julius Robert Oppenheimer ; April 22, 1904 – February 18, 1967) was an American theoretical physicist who served as the director of the Manhattan Project's Los Alamos Laboratory during World War II. He is often ...
to join the Manhattan Project at its new laboratory in
Los Alamos, New Mexico Los Alamos (, meaning ''The Poplars'') is a census-designated place in Los Alamos County, New Mexico, United States, that is recognized as one of the development and creation places of the Nuclear weapon, atomic bomb—the primary objective of ...
. It was at Bacher's insistence that Los Alamos became a civilian rather than a military laboratory. At Los Alamos, Bacher headed the project's P (Physics) Division, and later its G (Gadget) Division. Bacher worked closely with Oppenheimer, and the two men discussed the project's progress on a daily basis. After the war, Bacher became director of the Laboratory of Nuclear Studies at Cornell. He also served on the U.S. Atomic Energy Commission, the civilian agency that replaced the wartime Manhattan Project, and in 1947 he became one of its inaugural commissioners. He left in 1949 to become head Division of Physics, Mathematics, and Astronomy at Caltech. He was appointed a member of the
President's Science Advisory Committee The President's Science Advisory Committee (PSAC) was created on November 21, 1957, by President of the United States Dwight D. Eisenhower, as a direct response to the Soviet launching of the Sputnik 1 and Sputnik 2 satellites. PSAC was an upgra ...
(PSAC) in 1958. In 1962, he became Caltech's vice president and provost. He stepped down from the post of provost in 1970, and became a
professor emeritus ''Emeritus/Emerita'' () is an honorary title granted to someone who retirement, retires from a position of distinction, most commonly an academic faculty position, but is allowed to continue using the previous title, as in "professor emeritus". ...
in 1976. He died in 2004 at the age of 99.


Early life and career

Bacher was born in
Loudonville, Ohio Loudonville is a village in Ashland and Holmes counties in the U.S. state of Ohio. The population was 2,786 at the 2020 census. Loudonville is nicknamed the "Canoe Capital of Ohio" for the many canoe liveries along the Mohican River. It is al ...
, on August 31, 1905, the only child of Harry and Byrl Fox Bacher. In 1908, the family moved to
Ann Arbor, Michigan Ann Arbor is a city in Washtenaw County, Michigan, United States, and its county seat. The 2020 United States census, 2020 census recorded its population to be 123,851, making it the List of municipalities in Michigan, fifth-most populous cit ...
, where Harry worked as a banker and Byrl as a voice teacher on the
University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...
faculty. Bacher attended the W. S. Perry School, and later Ann Arbor High School. While there he met Professor Harrison M. Randall, the head of the physics department at the University of Michigan, who encouraged him to study physics. Bacher entered the University of Michigan, where he joined the
Kappa Sigma Kappa Sigma (), commonly known as Kappa Sig or KSig, is an American collegiate social fraternity founded at the University of Virginia in 1869. Kappa Sigma is one of the five largest international Fraternities and sororities in North America, fr ...
fraternity A fraternity (; whence, "wikt:brotherhood, brotherhood") or fraternal organization is an organization, society, club (organization), club or fraternal order traditionally of men but also women associated together for various religious or secular ...
and lived in the frat house. He became the house manager in his
sophomore year In the United States, a sophomore ( or ) is a person in the second year at an educational institution; usually at a secondary school or at the college and university level, but also in other forms of post-secondary educational institutions. In ...
, but moved back home in his junior year to concentrate on physics. At Randall's suggestion he applied to the
Harvard Graduate School of Arts and Sciences The Harvard Kenneth C. Griffin Graduate School of Arts and Sciences (GSAS) is the largest of the twelve graduate schools of Harvard University, when measured by the number of degree-seeking students. Formed in 1872, GSAS is responsible for most o ...
, which he entered in 1926 to study for his doctorate. His fees were paid by his family, but his father had a heart attack and could no longer afford them, so in 1927 Bacher moved back to Ann Arbor, where he lived at home, and attended the University of Michigan. He received a Charles A. Coffin Foundation Fellowship from
General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...
. To build up the theoretical physics department at the University of Michigan, Randall recruited four distinguished young physicists to work at Ann Arbor in 1927: Otto Laporte,
George Uhlenbeck George Eugene Uhlenbeck (December 6, 1900 – October 31, 1988) was a Dutch-American theoretical physicist, known for his significant contributions to quantum mechanics and statistical mechanics. He co-developed the concept of electron spin, alo ...
,
Samuel Goudsmit Samuel Abraham Goudsmit (July 11, 1902 – December 4, 1978) was a Dutch-American physicist famous for jointly proposing the concept of electron spin with George Eugene Uhlenbeck in 1925. Life and career Goudsmit was born in The Hague, Ne ...
, and David M. Dennison. The University of Michigan was no longer a backwater in theoretical physics. Bacher immediately signed up for Goudsmit's course on atomic structure. With Goudsmit he investigated the
Zeeman effect The Zeeman effect () is the splitting of a spectral line into several components in the presence of a static magnetic field. It is caused by the interaction of the magnetic field with the magnetic moment of the atomic electron associated with ...
of
hyperfine structure In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate electronic energy levels and the resulting splittings in those electronic energy levels of atoms, molecules, and ions, due to electromagnetic multipole int ...
of atomic levels, which became the subject of his 1930
PhD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...
thesis. On May 30, 1930, Bacher married Jean Dow. His mother gave them a Ford Model A and the use of the family's lakeside holiday house, where they entertained guests including
Paul Ehrenfest Paul Ehrenfest (; 18 January 1880 – 25 September 1933) was an Austrian Theoretical physics, theoretical physicist who made major contributions to statistical mechanics and its relation to quantum physics, quantum mechanics, including the theory ...
and
Enrico Fermi Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian and naturalized American physicist, renowned for being the creator of the world's first artificial nuclear reactor, the Chicago Pile-1, and a member of the Manhattan Project ...
. In 1931, with a National Research Council Fellowship, he spent a year at the
California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...
(Caltech) because Ira Bowen taught there. At Caltech Bacher attended lectures by
Robert Oppenheimer J. Robert Oppenheimer (born Julius Robert Oppenheimer ; April 22, 1904 – February 18, 1967) was an American theoretical physicist who served as the director of the Manhattan Project's Los Alamos Laboratory during World War II. He is often ...
, but spent most of his time at the Mt. Wilson Observatory, which had a better library. Bacher decided to create a work listing the energy,
coupling constant In physics, a coupling constant or gauge coupling parameter (or, more simply, a coupling), is a number that determines the strength of the force exerted in an interaction. Originally, the coupling constant related the force acting between tw ...
, parity and electron configurations of all the known atoms and
ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
s, working with Goudsmit back in Ann Arbor. The result was a book, ''Atomic Energy States as Derived from the Analysis of Optical Spectra'' (1932), which they dedicated to Randall. In the second year of his National Research Council Fellowship, Bacher moved across the country to the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
to work with John C. Slater, who had taught Bacher at Harvard. While there, Slater asked him to conduct a seminar on
James Chadwick Sir James Chadwick (20 October 1891 – 24 July 1974) was an English nuclear physicist who received the Nobel Prize in Physics in 1935 for his discovery of the neutron. In 1941, he wrote the final draft of the MAUD Report, which inspired t ...
's recent discovery of the
neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...
. Reading Chadwick's paper, he realized that anomalies in then-current theory would be resolved if the
spin Spin or spinning most often refers to: * Spin (physics) or particle spin, a fundamental property of elementary particles * Spin quantum number, a number which defines the value of a particle's spin * Spinning (textiles), the creation of yarn or thr ...
of the neutron was . This became the subject of a letter he submitted to the ''
Physical Review ''Physical Review'' is a peer-reviewed scientific journal. The journal was established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the Ame ...
'' with
visiting scholar In academia, a visiting scholar, visiting scientist, visiting researcher, visiting fellow, visiting lecturer, or visiting professor is a scholar from an institution who visits a host university to teach, lecture, or perform research on a topic fo ...
Edward Condon Edward Uhler Condon (March 2, 1902 – March 26, 1974) was an American nuclear physicist, a pioneer in quantum mechanics, and a participant during World War II in the development of radar and, very briefly, of nuclear weapons as part of the Ma ...
. A year later, Bacher became the first to suggest the neutron had a magnetic moment equal to about minus one
nuclear magneton The nuclear magneton (symbol ) is a physical constant of magnetic moment, defined in SI units by: \mu_\text = and in Gaussian CGS units by: \mu_\text = where: * is the elementary charge, * is the reduced Planck constant, * is the proton ...
, based on the unusually small magnetic moment of
nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
determined from its hyperfine structure. Afterwards Bacher returned to the University of Michigan on an Alfred H. Lloyd Fellowship. Jobs were hard to find at this time due to the
Great Depression The Great Depression was a severe global economic downturn from 1929 to 1939. The period was characterized by high rates of unemployment and poverty, drastic reductions in industrial production and international trade, and widespread bank and ...
, and in 1934 he accepted a job at
Columbia University Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...
, where he worked with
Isidor Isaac Rabi Israel Isidor Isaac Rabi (; ; July 29, 1898 – January 11, 1988) was an American nuclear physicist who received the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance imaging. H ...
, Jerrold Zacharias, Jerome Kellogg and Sid Millman. However it was difficult living in New York on his salary, and Jean gave birth to their first child, Martha, in December 1935. A second child, Andrew, was born in 1938. Bacher therefore accepted an offer from
Hans Bethe Hans Albrecht Eduard Bethe (; ; July 2, 1906 – March 6, 2005) was a German-American physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics and solid-state physics, and received the Nobel Prize in Physi ...
to work with him at
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
in
Ithaca, New York Ithaca () is a city in and the county seat of Tompkins County, New York, United States. Situated on the southern shore of Cayuga Lake in the Finger Lakes region of New York (state), New York, Ithaca is the largest community in the Ithaca metrop ...
. Ithaca was a university town similar to Ann Arbor, where Bacher and Jean had been raised. At Cornell Bacher worked with Bethe on his book ''Nuclear Physics. A: Stationary States of Nuclei'' (1936), the first of three books that would become known as the "Bethe Bible".


World War II


Radiation Laboratory

In December 1940 Bacher joined the
Radiation Laboratory The Radiation Laboratory, commonly called the Rad Lab, was a microwave and radar research laboratory located at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. It was first created in October 1940 and operated until 3 ...
at MIT, but did not immediately cease his research. He reached an arrangement with its director, Lee Alvin DuBridge, to return to Cornell for four days every three weeks until it was completed. He was researching the
neutron cross section In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm2 for which the number of ...
of
cadmium Cadmium is a chemical element; it has chemical symbol, symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Like z ...
, a topic of interest to Enrico Fermi, who was attempting to build a
nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...
, but whose figures did not agree with Bacher's. Bacher carefully checked his results, and Fermi, convinced of their correctness, urged Bacher to publish them. Bacher submitted a paper to the ''Physical Review'' with instructions to withhold publication until after the war, and the paper was not published until 1946. DuBridge organized the Radiation Laboratory into two sections, one for incoming
radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
signals, and one for outgoing radar signals. Bacher was appointed to handle the incoming signals section. Here he gained valuable experience in administration, coordinating not just the efforts of his scientists, but also those of General Electric and
RCA RCA Corporation was a major American electronics company, which was founded in 1919 as the Radio Corporation of America. It was initially a patent pool, patent trust owned by General Electric (GE), Westinghouse Electric Corporation, Westinghou ...
. He later recalled:


Manhattan Project

In 1942, Bacher and Rabi, the Radiation Laboratory's assistant director, were approached by Oppenheimer to join the
Manhattan Project The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the ...
at its new laboratory in Los Alamos, New Mexico. They convinced Oppenheimer that the plan for a military laboratory would not work, since a scientific effort would need to be a civilian affair. The plan was modified, and the new laboratory would be a civilian one, run by the
University of California The University of California (UC) is a public university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...
under contract from the War Department. Bacher felt that this was his first contribution to the success of the project. He met with Oppenheimer at Los Alamos in April 1943, but was not convinced that he was needed. Oppenheimer wrote to him that: Bacher then accepted the job at Los Alamos, moving there in May 1943 with his family to become the head of the Experimental Physics Division (P Division). His wife Jean Dow Bacher was also hired to work as a
human computer The term "computer", in use from the early 17th century (the first known written reference dates from 1613), meant "one who computes": a person performing mathematical calculations, before electronic calculators became available. Alan Turing ...
in the Theoretical Division (T Division). For his seven group leaders he had John H. Williams, Robert R. Wilson, John H. Manley, Darol K. Froman, Emilio G. Segrè, Bruno B. Rossi and Donald W. Kerst. Bacher worked closely with Oppenheimer, and the two men discussed the project's progress on a daily basis. In July 1944, Oppenheimer reorganized the laboratory to focus on the problem of building an
implosion-type nuclear weapon Nuclear weapons design are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types: # Pure fission weapons are the simplest, least technically de ...
, which was necessary because the gun-type design would not work with
plutonium Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four ...
. P Division was broken up, and Bacher became the head of the G (for Gadget) Division. This much larger division contained eleven groups headed by leaders who included
William Higinbotham William Alfred Higinbotham (October 22, 1910 – November 10, 1994) was an American physicist. A member of the team that developed the first nuclear bomb, he later became a leader in the nonproliferation movement. He also has a place in the hi ...
, Seth Neddermeyer,
Edwin McMillan Edwin Mattison McMillan (September 18, 1907 – September 7, 1991) was an American physicist credited with being the first to produce a transuranium element, neptunium. For this, he shared the 1951 Nobel Prize in Chemistry with Glenn Seaborg. ...
, Luis Alvarez and
Otto Frisch Otto Robert Frisch (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Otto Stern and Immanuel Estermann, he first measured the magnetic moment of the proton. With his aunt, Lise M ...
. While George Kistiakowsky's Explosives Division (X Division) developed the
explosive lens An explosive lens—as used, for example, in nuclear weapons—is a highly specialized shaped charge. In general, it is a device composed of several explosive charges. These charges are arranged and formed with the intent to control the sha ...
es, G Division designed the rest of the weapon. There were numerous difficulties to overcome, not the least of which was devising a means of detonating the lenses with the required speed.
Robert F. Christy Robert Frederick Christy (May 14, 1916 – October 3, 2012) was a Canadian-American theoretical physicist and later astrophysicist who was one of the last surviving people to have worked on the Manhattan Project during World War II. He briefly ...
's solid
core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (laboratory), a highly specialized shared research resource * Core (manufacturing), used in casting and molding * Core (optical fiber ...
design was chosen as the most likely design to succeed. To coordinate the efforts of the laboratory, Oppenheimer created the "Cowpuncher Committee", so-called because they were to "ride herd" on the implosion effort and coordinate all the efforts of the laboratory. It included Bacher, along with Samuel Allison, George Kistiakowsky, Deak Parsons, Charles Lauritsen and Hartley Rowe. Three days before the day the bomb was to be test detonated in the
New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
desert, Bacher was part of the pit assembly team, which assembled the nuclear capsule (a cylindrical section of the uranium tamper, containing the plutonium core and initiator) in an old farmhouse near the
Alamogordo Alamogordo () is a city in and the county seat of Otero County, New Mexico, Otero County, New Mexico, United States. A city in the Tularosa Basin of the Chihuahuan Desert, it is bordered on the east by the Sacramento Mountains (New Mexico), Sac ...
testing site. When the capsule was driven to the shot tower and inserted into the spherical tamper, inside the explosive assembly, it stuck. Bacher recognized that expansion of the capsule due to the heat given off by the plutonium core was causing the jam, and that leaving the two parts in contact would equalize temperatures and allow the capsule to be inserted fully. After watching the test, his reaction was merely "Well, it works." Bacher was packaging the third core for shipment to
Tinian Tinian () is one of the three principal islands of the Commonwealth of the Northern Mariana Islands (CNMI). Together with uninhabited neighboring Aguiguan, it forms Tinian Municipality, one of the four constituent municipalities of the Northern ...
on August 12 at the Ice House at Los Alamos when he received word that the Japanese had initiated surrender negotiations. He had already set G Division the task of designing and building new types of cores and assemblies, and he co-authored a report with Robert Wilson urging the development of
Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...
's
Super Super may refer to: Computing * SUPER (computer program), or Simplified Universal Player Encoder & Renderer, a video converter/player * Super (computer science), a keyword in object-oriented programming languages * Super key (keyboard butto ...
bomb. He served on a committee chaired by
Richard Tolman Richard Chace Tolman (March 4, 1881 – September 5, 1948) was an American mathematical physicist and physical chemist who made many contributions to statistical mechanics and theoretical cosmology. He was a professor at the California In ...
that looked into declassifying documents produced by the Manhattan Project, and one chaired by Manson Benedict that investigated the technical feasibility of international control of nuclear energy. For his services to the Manhattan Project Bacher was awarded the
Medal for Merit The Medal for Merit was the highest civilian decoration of the United States in the gift of the president. Created during World War II, it was awarded by the president of the United States to civilians who "distinguished themselves by exceptiona ...
on January 12, 1946.


Post-World War II


Atomic Energy Commission

After the war, Bacher returned to Ithaca to head Cornell's Laboratory for Nuclear Studies. He agreed with Bethe that what Cornell needed to become a major player in high energy nuclear physics was a new
synchrotron A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The strength of the magnetic field which bends the particle beam i ...
, but first he needed to find somewhere to put it. However, in 1946 Bacher was appointed to the Scientific and Technical Subcommittee of the new
United Nations Atomic Energy Commission The United Nations Atomic Energy Commission (UNAEC) was founded on 24 January 1946 by the very first resolution of the United Nations General Assembly "to deal with the problems raised by the discovery of atomic energy." The General Assembly aske ...
, along with fellow United States representatives Tolman and Oppenheimer. Bacher therefore had to divide his time between Ithaca and New York City. In October 1946 David Lilienthal asked Bacher to become one of the inaugural commissioners of the
United States Atomic Energy Commission The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by the U.S. Congress to foster and control the peacetime development of atomic science and technology. President Harry ...
, the civilian agency that was being formed to replace the wartime Manhattan Project. As a Republican, Bacher was easily confirmed by the
Senate A senate is a deliberative assembly, often the upper house or chamber of a bicameral legislature. The name comes from the ancient Roman Senate (Latin: ''Senatus''), so-called as an assembly of the senior (Latin: ''senex'' meaning "the el ...
members of the
United States Congress Joint Committee on Atomic Energy The Joint Committee on Atomic Energy (JCAE) was a United States congressional committee that was tasked with exclusive jurisdiction over "all bills, resolutions, and other matters" related to civilian and military aspects of nuclear power from 194 ...
by an 8–0 vote. As he was the only one of the five commissioners who was a scientist—an important factor in his decision to accept the post—he played a leading role in the selection of the Atomic Energy Commission's influential General Advisory Committee to which nine scientists were appointed: James Conant, Lee DuBridge, Enrico Fermi, Robert Oppenheimer, Isidor Isaac Rabi, Hartley Rowe,
Glenn Seaborg Glenn Theodore Seaborg ( ; April 19, 1912February 25, 1999) was an American chemist whose involvement in the synthesis, discovery and investigation of ten transuranium elements earned him a share of the 1951 Nobel Prize in Chemistry. His work i ...
, Cyril Stanley Smith and Hood Worthington. Bacher and fellow commissioner Sumner Pike began with an inspection of Los Alamos and the
Hanford Site The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. It has also been known as SiteW and the Hanford Nuclear R ...
, and conducted an inventory of the fissionable material at Los Alamos with Norris Bradbury, who had succeeded Oppenheimer as its director. He found that only nine atomic bombs had been built in 1946; only four would be in 1947, primarily due to production problems with the reactors at Hanford. These problems were on their way to resolution when Bacher observed the Operation Sandstone nuclear tests at
Enewetak Atoll Enewetak Atoll (; also spelled Eniwetok Atoll or sometimes Eniewetok; , , or , ; known to the Japanese as Brown Atoll or Brown Island; ) is a large coral atoll of 40 islands in the Pacific Ocean and with its 296 people (as of 2021) forms a leg ...
in 1948 as the Atomic Energy Commission's representative. Bacher's original two-year term would have expired on January 1, 1949, but President
Harry Truman Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. As the 34th vice president in 1945, he assumed the presidency upon the death of Franklin D. Roosevelt that year. Subsequen ...
convinced him to stay on. Bacher resigned in May 1949, and this time the President was unable to dissuade him. Bacher wished to return to academia, but Robert Wilson was now the head of Cornell's Laboratory for Nuclear Studies, and Bacher felt that it would be awkward working for someone who was one of his group leaders at Los Alamos. He therefore accepted an offer from Lee DuBridge of the chair of the Division of Physics, Mathematics, and Astronomy at Caltech. However the work at the Atomic Energy Commission was not so easily left behind. Senator Bourke Hickenlooper charged the commission with mismanagement, specifically cost overruns at Hanford, awarding a scholarship to a
communist Communism () is a sociopolitical, philosophical, and economic ideology within the socialist movement, whose goal is the creation of a communist society, a socioeconomic order centered on common ownership of the means of production, di ...
, and the loss of of uranium from the
Argonne National Laboratory Argonne National Laboratory is a Federally funded research and development centers, federally funded research and development center in Lemont, Illinois, Lemont, Illinois, United States. Founded in 1946, the laboratory is owned by the United Sta ...
. Bacher felt obligated to return to Washington to testify on Lilienthal's behalf before the Joint Committee on Atomic Energy. Another crisis broke in September 1949 when the Air Force picked up signs of the
Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
's
RDS-1 The RDS-1 (), also known as Izdeliye 501 (device 501) and First Lightning (), was the nuclear bomb used in the Soviet Union's first nuclear weapon test. The United States assigned it the code-name Joe-1, in reference to Joseph Stalin. It was de ...
nuclear test. Bacher joined Oppenheimer, Parsons,
General A general officer is an Officer (armed forces), officer of high rank in the army, armies, and in some nations' air force, air and space forces, marines or naval infantry. In some usages, the term "general officer" refers to a rank above colone ...
Hoyt Vandenberg Hoyt Sanford Vandenberg (January 24, 1899 – April 2, 1954) was a United States Air Force general. He served as the second Chief of Staff of the Air Force, and the second Director of Central Intelligence. During World War II, Vandenberg was t ...
, the Atomic Energy Commissioners and a British delegation under William Penney to discuss what to do. The recent devaluation of the British pound had already triggered a financial crisis, and there was concern about how the markets would react to the news. Oppenheimer and Bacher saw the evidence of a nuclear test as conclusive, and Bacher in particular came down strongly on the side of making a public announcement, as the number of people who already knew made a leak almost inevitable. Truman made the announcement a few days later.


Caltech

The division chair that Bacher now occupied at Caltech had been vacant since Robert A. Millikan had retired in 1945. Although nominally a professorship, it was primarily an administrative post. In 1949 there were 17 professors in the department, of whom nine were physicists, two were astrophysicists, and the remaining six were mathematicians. There were two world class research laboratories funded by the
Office of Naval Research The Office of Naval Research (ONR) is an organization within the United States Department of the Navy responsible for the science and technology programs of the U.S. Navy and Marine Corps. Established by Congress in 1946, its mission is to plan ...
, the Cosmic Ray Laboratory that had been founded by Millikan, which was now directed by Carl Anderson, and the W. K. Kellogg Radiation Laboratory which was directed by Charles Lauritsen. But there were no facilities for high energy physics; these would have to be created from scratch. In moving into high energy physics Bacher had the full support not just of DuBridge, but of Anderson and Lauritsen as well. Lauritsen had already hired Robert Langmuir to begin designing a new 600 MeV synchrotron, and Bacher found a large building to house it that had originally been used for grinding and polishing the Palomar Observatory's mirror, but which had been empty since 1948. He arranged for Atomic Energy Commission and Office of Naval Research grants worth $1 million to build it and the other required facilities, and $300,000 a year to run it. Facilities were not enough; Bacher needed physicists. Lauritsen had made a start on this too, by hiring Robert Christy. Bacher hired experimental physicists Alvin V. Tollestrup, Robert M. Walker and Matthew Sands. The physicist that Bacher decided he wanted most, though, was
Richard Feynman Richard Phillips Feynman (; May 11, 1918 – February 15, 1988) was an American theoretical physicist. He is best known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of t ...
. To get him, Bacher offered a large salary, and agreed to pay for Feynman's 1950–1951 sabbatical in Brazil. Feynman would go on to win the
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
in 1965. In 1955 Bacher hired
Murray Gell-Mann Murray Gell-Mann (; September 15, 1929 – May 24, 2019) was an American theoretical physicist who played a preeminent role in the development of the theory of elementary particles. Gell-Mann introduced the concept of quarks as the funda ...
, who would win the Nobel Prize in 1969. The relatively new field of
radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
sparked Bacher's interest, and he hired
John Bolton John Robert Bolton (born November 20, 1948) is an American attorney, diplomat, Republican Party (United States), Republican consultant, and political commentator. He served as the 25th United States ambassador to the United Nations from 2005 to ...
and Gordon Stanley from the Australian
Commonwealth Scientific and Industrial Research Organisation The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency that is responsible for scientific research and its commercial and industrial applications. CSIRO works with leading organisations arou ...
in 1955. A grant from the Office of Naval Research allowed Bolton to build the Owens Valley Radio Observatory, which became an important center for the study of
quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...
s. Caltech did not spell an end to Bacher's service in Washington. He served two terms as a member of the
President's Science Advisory Committee The President's Science Advisory Committee (PSAC) was created on November 21, 1957, by President of the United States Dwight D. Eisenhower, as a direct response to the Soviet launching of the Sputnik 1 and Sputnik 2 satellites. PSAC was an upgra ...
(PSAC) under President
Dwight D. Eisenhower Dwight David "Ike" Eisenhower (born David Dwight Eisenhower; October 14, 1890 – March 28, 1969) was the 34th president of the United States, serving from 1953 to 1961. During World War II, he was Supreme Commander of the Allied Expeditionar ...
, from November 18, 1953, to June 30, 1955, and from December 9, 1957, to December 31, 1959. During his first term he testified on behalf of his old friend at the
Oppenheimer security hearing Over four weeks in 1954, the United States Atomic Energy Commission (AEC) explored the background, actions, and associations of J. Robert Oppenheimer, the American scientist who directed the Los Alamos Laboratory during World War II as part of t ...
in 1954. During his second, he worked with James Fisk and
Ernest Lawrence Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was an American accelerator physicist who received the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation for ...
to examine how a
Partial Nuclear Test Ban Treaty The Partial Test Ban Treaty (PTBT), formally known as the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, prohibited all nuclear weapons testing, test detonations of nuclear weapons except for those co ...
could be monitored. Bacher remained chair of the division of physics, mathematics and astronomy at Caltech until 1962, when he was appointed as vice president and provost. He stepped down from the post of provost in 1970 at the age of 65, and became a
professor emeritus ''Emeritus/Emerita'' () is an honorary title granted to someone who retirement, retires from a position of distinction, most commonly an academic faculty position, but is allowed to continue using the previous title, as in "professor emeritus". ...
in 1976. He still did some research at the
Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by Cali ...
, and visited Caltech from time to time. In 1983 he was master of ceremonies at Los Alamos for events commemorating the 40th anniversary of the founding of the laboratory in 1943. In his lifetime, he was elected to the
National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...
, the
American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
, and the
American Academy of Arts and Sciences The American Academy of Arts and Sciences (The Academy) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other ...
. Bacher died on November 18, 2004, at a retirement home in
Montecito, California Montecito (archaic use of Spanish for woodland or countryside) is an unincorporated town in Santa Barbara County, California, United States.McCormack, Don (1999). ''McCormack's Guides Santa Barbara and Ventura 2000''. Mccormacks Guides. p. 58. ...
. He was survived by his daughter, Martha Bacher Eaton, and son, Andrew Dow Bacher, a nuclear physicist working at
Indiana University Indiana University (IU) is a state university system, system of Public university, public universities in the U.S. state of Indiana. The system has two core campuses, five regional campuses, and two regional centers under the administration o ...
, his wife Jean having died on May 28, 1994. His papers are in the California Institute of Technology Archives.


Notes


References

* * * * * * *


External links


1983 Audio Interview with Robert Bacher by Martin Sherwin
Voices of the Manhattan Project
Annotated bibliography for Robert Bacher from the Alsos Digital Library for Nuclear Issues

Oral History interview transcript with Robert Bacher on 30 June 1966, American Institute of Physics, Niels Bohr Library and ArchivesOral History interview transcript with Robert Bacher on 13 February 1986, American Institute of Physics, Niels Bohr Library and Archives
{{DEFAULTSORT:Bacher, Robert 1905 births 2004 deaths People from Loudonville, Ohio Scientists from Ann Arbor, Michigan People from Los Alamos, New Mexico American nuclear physicists Manhattan Project people Cornell University faculty California Institute of Technology faculty Fellows of the American Academy of Arts and Sciences Columbia University staff University of Michigan College of Literature, Science, and the Arts alumni Fellows of the American Physical Society Presidents of the International Union of Pure and Applied Physics Presidents of the American Physical Society Members of the American Philosophical Society Pioneer High School (Ann Arbor, Michigan) alumni