Norris Edwin Bradbury (May 30, 1909 – August 20, 1997), was an Americanphysicist who served as director of theLos Alamos National Laboratory for 25 years from 1945 to 1970. He succeededRobert Oppenheimer, who personally chose Bradbury for the position of director after working closely with him on theManhattan Project duringWorld War II. Bradbury was in charge of the final assembly of "the Gadget", detonated in July 1945 for theTrinity test.

Norris Bradbury
Born	(1909-05-30)May 30, 1909 Santa Barbara, California, US
Died	August 20, 1997(1997-08-20) (aged 88) Los Alamos, New Mexico, US
Education	Pomona College (BA) University of California, Berkeley (PhD)
Known for	SucceededJ. Robert Oppenheimer as director of theLos Alamos National Laboratory
Awards	Legion of Merit (1945) Department of Defense Medal for Distinguished Public Service (1966) Enrico Fermi Award (1970)
Scientific career
Fields	Physics
Institutions	Stanford University University of California Los Alamos National Laboratory
Thesis	Studies on the Mobility of Gaseous Ions (1932)
Doctoral advisor	Leonard B. Loeb
Signature

Bradbury took charge at Los Alamos at a difficult time. Staff were leaving in droves, living conditions were poor and there was a possibility that the laboratory would close. He managed to persuade enough staff to stay and got the University of California to renew the contract to manage the laboratory. He pushed continued development of nuclear weapons, transforming them from laboratory devices to production models. Numerous improvements made them safer, more reliable and easier to store and handle, and made more efficient use of scarce fissionable materiel.

In the 1950s Bradbury oversaw the development ofthermonuclear weapons, although a falling-out withEdward Teller over the priority given to their development led to the creation of a rival nuclear weapons laboratory, theLawrence Livermore Laboratory. In later years, he branched out, constructing theLos Alamos Meson Physics Facility to develop the laboratory's role in nuclear science, and during theSpace Race of the 1960s, the laboratory developed theNuclear Engine for Rocket Vehicle Application (NERVA). TheBradbury Science Museum is named in his honor.

Norris Bradbury was born inSanta Barbara, California, on May 30, 1909,^[1] one of four children of Edwin Perley Bradbury and his wife Elvira née Clausen. One sister died as an infant, and the family adopted twins Bobby and Betty, both of whom served in theUnited States Marine Corps duringWorld War II. Bradbury was educated atHollywood High School andChaffey High School inOntario, California, graduating at the age of 16. He then attendedPomona College inClaremont, California, from which he graduatedsumma cum laude with a Bachelor of Arts (BA) inchemistry in 1929. This earned him membership ofPhi Beta Kappa society.^[2][3] At Pomona, he met Lois Platt, an English Literature major who was the sister of his college roommate. They were married in 1933,^[4] and had three sons, James, John, and David.^[5] Norris was an active member of an Episcopal church.^[6]

Bradbury became interested inphysics and did graduate work at theUniversity of California, Berkeley, where he was a teaching fellow from 1929 to 1931. He submitted a PhD thesis onStudies on the Mobility of Gaseous Ions under the supervision ofLeonard B. Loeb, and was awarded aNational Research Council fellowship.^[7][8][9]

As well as supervising Bradbury's thesis, Loeb, who had served as a naval reservist duringWorld War I, encouraged Bradbury to apply for a commission as a naval reservist. Bradbury's commission as anensign was signed byLieutenant CommanderChester W. Nimitz, who was the head of theNaval Reserve Officer Training Corps at Berkeley at the time.^[10]

After two years at theMassachusetts Institute of Technology, Bradbury became an assistant professor of physics atStanford University in 1935, rising to become an associate professor in 1938, and a full professor in 1943. He became an expert on theelectrical conductivity of gases, the properties ofions, and the behavior ofatmospheric electricity, publishing in journals including thePhysical Review,Journal of Applied Physics,Journal of Chemical Physics, and theJournal of Atmospheric Electricity and Terrestrial Magnetism.^[7] He invented theBradbury-Nielsen shutter, a type of electrical ion gate,^[11] widely used inmass spectrometry in bothtime-of-flight mass spectrometers andion mobility spectrometers.^[12]

Bradbury was called up for service in World War II in early 1941, although the Navy allowed him to stay at Stanford until the end of the academic year. He was then sent to theNaval Proving Ground atDahlgren, Virginia, to work onexternal ballistics. Already working at Dahlgren were Loeb andCommanderDeak Parsons.^[10]

In June 1944, Bradbury received orders from Parsons, who was now the deputy director of theManhattan Project'sLos Alamos Laboratory, to report toAlbuquerque, New Mexico. Parsons explained that he needed Bradbury to work on theexplosive lenses required by animplosion-type nuclear weapon. Bradbury was less than enthusiastic about the prospect, but he was a naval officer, and ultimately agreed to go.^[13][14]

At Los Alamos, Bradbury became head of E-5, the Implosion Experimentation Group,^[15] which put him in charge of the implosion field test program.^[16] In August, the laboratory's director,Robert Oppenheimer, implemented a sweeping reorganization. E-5 became part ofGeorge Kistiakowsky's new Explosives Division (X Division), and was renumbered X-1.^[17] At this point, Bradbury was leading some of the most critical work at the laboratory, as it struggled with thejets that spoiled the perfect spherical shape desired for the implosion process. These were examined with a combination of magnetic,X-ray andRaLa techniques.^[18]

In March 1945, Oppenheimer createdProject Alberta under Parsons to carry out the Manhattan Project's ultimate mission: the preparation and delivery of nuclear weapons in combat. Bradbury was transferred to Project Alberta to head theFat Man assembly group.^[19] In July 1945, Bradbury supervised the preparation of "the Gadget", as the bomb was known, at theTrinity nuclear test.^[20][21] "For me to say", Bradbury later recalled, "I had any deep emotional thoughts about Trinity... I didn't. I was just damned pleased that it went off."^[22]

Oppenheimer submitted his resignation as director of the Los Alamos Laboratory, but remained until a successor could be found. The director of the Manhattan Project,Major GeneralLeslie R. Groves, Jr., wanted someone with both a solid academic background and a high standing within the project. Oppenheimer recommended Bradbury. This was agreeable to Groves, who liked the fact that as a naval officer Bradbury was both a military man and a scientist. Bradbury accepted the offer on a six-month trial basis.^[23][7]

Parsons arranged for Bradbury to be quickly discharged from the Navy,^[24] which awarded him theLegion of Merit for his wartime services.^[25] He remained in the Naval Reserve, though, ultimately retiring in 1961 with the rank of captain.^[26] On October 16, 1945, there was a ceremony at Los Alamos at which Groves presented the laboratory with theArmy-Navy "E" Award, and presented Oppenheimer with a certificate of appreciation. Bradbury became the laboratory's second director the following day.^[27][7]

The first months of Bradbury's directorship were particularly difficult. He had hoped thatAtomic Energy Act of 1946 would be quickly passed by Congress and the wartime Manhattan Project would be superseded by a new, permanent organization. It soon became clear that this would take more than six months. PresidentHarry S. Truman did not sign the act creating theAtomic Energy Commission into law until August 1, 1946, and it did not become active until January 1, 1947. In the meantime, Groves' legal authority to act was limited.^[28]

Most of the scientists at Los Alamos were eager to return to their laboratories and universities, and by February 1946 all of the wartime division heads had left, but a talented core remained.Darol Froman became head ofRobert Bacher's G division, now renamed M Division. Eric Jette became responsible for Chemistry and Metallurgy,John H. Manley for Physics,George Placzek for Theory, Max Roy for Explosives, and Roger Wagner for Ordnance.^[27] The number of personnel at Los Alamos plummeted from its wartime peak of over 3,000 to around 1,000, but many were still living in temporary wartime accommodation. To make matters worse, the water pipe to Los Alamos froze and the water had to be supplied by tanker trucks.^[28] Despite the reduced staff, Bradbury still had to provide support forOperation Crossroads, the nuclear tests in the Pacific.^[29]

Bradbury pushed continued development of nuclear weapons to take them from laboratory devices to production models. There were numerous improvements that could make them more safe, reliable and easy to store and handle, and make more efficient use of scarce fissionable materiel. While Bradbury gave priority to improved fission weapons, research still continued on "Alarm Clock", a boosted nuclear weapon, and the "Super", athermonuclear weapons design.^[30] The new fission designs were tested duringOperation Sandstone in 1948. TheMark 4 nuclear bomb became the first nuclear weapon to be mass-produced on an assembly line.^[31]

As the future became more certain, Bradbury began looking for a new site for the laboratory away from the crowded town center. In 1948, Bradbury submitted a proposal to the Atomic Energy Commission for a new $107 million facility on the South Mesa, linked to the town by a new bridge over the canyon.^[31]

All this time, Bradbury remained nominally a professor in absentia at Stanford. The Los Alamos Laboratory was nominally run under a wartime contract with the University of California, but a clause in the contract allowed the University to terminate the contract three months after the end of the war. The university duly served notice, but Bradbury managed to get it rescinded, and in 1948 the contract was renewed. In 1951, he became a professor at the University of California.^[32][25]

By 1951, the laboratory had come up with theTeller-Ulam design, and thermonuclear tests were conducted duringOperation Greenhouse.^[33] Tensions between Bradbury andEdward Teller over the degree of priority given to thermonuclear weapons development led to the creation of a second nuclear weapons laboratory, theLawrence Livermore Laboratory.^[34]

In later years, Bradbury branched out, constructing theLos Alamos Meson Physics Facility to develop the laboratory's role in nuclear science.^[35] During theSpace Race of the 1960s, the laboratory worked onProject Rover, developing theNuclear Engine for Rocket Vehicle Application (NERVA). The laboratory demonstrated the feasibility and value of nuclear rocket propulsion.^[36]

For many years, Bradbury was responsible for much of the administration of the town of Los Alamos. The town established impressive health and education facilities. Eventually the new technical area was built outside the town, and on February 18, 1957, the security gates were taken down. Finally, the town became an incorporated community and the director's civic responsibilities ended.^[37][38]

In 1966, Bradbury was awarded theDepartment of Defense Medal for Distinguished Public Service for "exceptionally meritorious civilian service to the Armed Forces and the United States of America in a position of great responsibility as director, Los Alamos Scientific Laboratory".^[39] His citation went on to say that "The outstanding international reputation of the Los Alamos Laboratory is directly attributable to his exceptional leadership. The United States is indebted to Dr. Bradbury and his laboratory, to a very large degree, for our present nuclear capability."^[39] He also received theEnrico Fermi Award in 1970.^[39] In 1971, he received the Golden Plate Award of theAmerican Academy of Achievement.^[40]

Bradbury retired as director of Los Alamos Laboratory in 1970. His successor,Harold Agnew, invited him to become a senior consultant, but Bradbury declined the offer, although he did serve as a consultant for other government agencies, including theNational Academy of Sciences, and as a member of the boards of the Los Alamos Medical Center, the First National Bank of Santa Fe, the Los Alamos YMCA and the Santa Fe Neurological Society.^[41]

Norris' eldest son, James, also became a physicist and served as director of the Meson Physics Facility at Los Alamos. His youngest son David, with a Ph.D. inbiogeography, returned to Los Alamos and worked in environmental restoration for the Laboratory.^[42]

In 1969 thegovernor of New Mexico,David Cargo, appointed Bradbury as a regent of theUniversity of New Mexico, but this was a turbulent time for the university. In response to theKent State Shootings in May 1970, students and antiwar activistJane Fonda marched on the home of Ferrel Heady, the president of the University of New Mexico. When he refused to meet with them, the students called a strike. Classes were cancelled, rallies were held and students occupied the Student Union Building. Cargo called in theNew Mexico National Guard to remove them, and eleven people werebayoneted. Cargo's successor,Bruce King, replaced Bradbury and another regent.^[41][43]

In the mid-1990s, Bradbury accidentally hit his leg while chopping firewood.Gangrene set in, and his right leg was amputated below the knee. It spread to his left leg, and part of his left foot was amputated, leaving him in a wheelchair. The disease eventually proved fatal, and he died on August 20, 1997.^[44] He was survived by his wife Lois, who died in January 1998, and his three sons.^[5] A funeral service was held in Los Alamos, and he was buried at Guaje Pines Cemetery in Los Alamos.^[45]

• Agnew, Harold;Schreiber, Raemer E. (1998).Norris E. Bradbury 1909–1996: A Biographical Memoir(PDF). Washington, D.C.: National Academies Press.OCLC 79388516. RetrievedApril 6, 2013.
• Christman, Albert B. (1998).Target Hiroshima: Deak Parsons and the Creation of the Atomic Bomb. Annapolis, Maryland: Naval Institute Press.ISBN 1-55750-120-3.OCLC 38257982.
• Ebinger, Virginia Nylander (2006).Norris E. Bradbury 1909–1997. Los Alamos, New Mexico: Los Alamos Historical Society.ISBN 0-941232-34-4.OCLC 62408863.
• Hewlett, Richard G.; Anderson, Oscar E. (1962).The New World, 1939–1946(PDF). University Park: Pennsylvania State University Press.ISBN 0-520-07186-7.OCLC 637004643. RetrievedMarch 26, 2013.{{cite book}}:ISBN / Date incompatibility (help)
• Hewlett, Richard G.; Duncan, Francis (1969).Atomic Shield, 1947–1952. A History of the United States Atomic Energy Commission. University Park: Pennsylvania State University Press.ISBN 0-520-07187-5.OCLC 3717478.
• Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.;Westfall, Catherine L. (1993).Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press.ISBN 0-521-44132-3.OCLC 26764320.
• Hunner, Jon (2004).Inventing Los Alamos: The Growth of an Atomic Community. Norman: University of Oklahoma Press.ISBN 978-0-8061-3891-6.OCLC 154690200.

• 1985 Audio Interview with Norris Bradbury by Martin Sherwin Voices of the Manhattan Project
• "Interview with Norris Bradbury, 1986 [1]". WGBH Educational Foundation. RetrievedFebruary 26, 2014.
• "Interview with Norris Bradbury, 1986 [2]". WGBH Educational Foundation. RetrievedFebruary 26, 2014.