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At least 217 records · Page 12

‘Spokesperson for everyone at the Laboratory who believed in Oppenheimer’ Los Alamos physicist Fred Ribe’s 1954 petition protested former Lab Director’s revoked clearance

In 1953, J. Robert Oppenheimer received an ultimatum. The Atomic Energy Commission (AEC) sent the "father of the atomic bomb" and former Los Alamos Director a letter outlining two options: give up his Q clearance and role as advisor or appear before a board to prove that he wasn’t a threat to national security. Oppenheimer chose the latter. The ensuing saga that unfolded throughout 1954 peaked with a four-week, closed-door hearing in April and May after which Oppenheimer’s security clearance was formally revoked. The long, complex affair consisted of national security concerns, a tangle of questionable charges, divided opinions, loyalties, egos, and vendettas. AEC Chairman Lewis L. Strauss and Oppenheimer were at the center of events, though an important part of the historical record is Fred L. Ribe and the 493 other Los Alamos scientists who risked harming their careers to protest Oppenheimer’s ordeal. Ribe wrote a one-page letter, signed by his colleagues, to President Dwight Eisenhower and the AEC commissioners “objecting the decision and the grounds for it” as Ribe later wrote. This petition – and Strauss’s written response – were donated by Ribe and are part of the unclassified historical collections in the National Security Research Center, which is the Lab’s classified library.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

Operation Plumbbob

On June 24, 1957, a thirty-seven kiloton nuclear device, codenamed Priscilla, exploded 700 feet over the Nevada Test Site’s Frenchman dry lake. Below, on the lakebed, was a bank vault designed by the Mosler Safe Company for one of several Federal Civil Defense Administration experiments. The vault was constructed “to evaluate the effectiveness of a reinforced-concrete vault and steel vault door in providing protection against the effects of a nuclear detonation.” Blast damage to the exterior was largely confined to the side walls, whose concrete was stripped off; its steel reinforcing rods bent and twisted. The vault door was essentially undamaged and was opened with minimal difficulty. The vault contents - sandbags, movie camera, and thermometers - were only slightly disturbed. The camera operated as planned, running 40 ft of film. The film, however, was completely fogged. Two clinical type thermometers registered 88°F, and a 24-hr stylus American temperature recorder registered a constant 88°F. Priscilla was the fifth of twenty-nine tests conducted in 1957 as part of Operation Plumbbob, whose stated purpose was to conduct tests “aimed to attain new knowledge important to the defense of the United States and the Free World.” Individual events included “proof tests of air defense and antisubmarine warheads to be stockpiled, development tests of bomb components and mockups, and design tests of smaller and lighter warheads.” One test, John, was that of an air-to-air missile detonated 18,500 feet over the test site.

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Operation Redwing

Cherokee exploded with an impressive yield of 3.8 megatons but missed its aiming point by six miles. Although regrettable, the miss was not overly significant because the event proved “that the United States owned a real [thermonuclear] weapon.” Cherokee was the second of seventeen tests conducted during Operation Redwing, whose primary purpose was to proof test bombs and warheads for an emerging generation of weapon systems. Eleven tests took place at Enewetak Atoll and six at Bikini Atoll. The parsing of tests between the two atolls was based largely on expected yields. Lower yield tests were held at Enewetak with the expectation that they would not impact the permanent tests facilities located on the atoll. Higher yield shots were detonated at Bikini. Although this division worked for the most part, fallout from one Bikini test, Tewa, reached Enewetak, contaminating both personnel and permanent test facilities.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

How nuclear weapons tests were named

What do Galileo, Husky Pup, Turquoise and Barracuda have in common? They are names of nuclear weapons tests conducted at what is now called the Nevada National Security Site (NNSS). Over 1,000 U.S. nuclear tests were conducted at various sites between 1945 and 1992, and each of the tests was inaugurated with a name, as documented in the Lab’s vast weapons test collections housed in the National Security Research Center (NSRC). To protect the classified information about nuclear weapons and maintain security, nuclear weapons tests were assigned names. This has been true from the beginning with Trinity, the first atomic bomb test in 1945. Lab Director J. Robert Oppenheimer later said the test name may have been inspired by his love of poetry.

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Witness the Trinity test through Lab artifacts

July 16 marks the 77th anniversary of the Trinity test, conducted in a desert in New Mexico. The test subject, an atomic bomb called The Gadget, was successfully detonated from a 100-foot steel tower. This event marks the commencement of the Atomic Age, a new era where fission capabilities could be employed for national security purposes. Shortly after the Trinity test, two Los Alamos-created atomic weapons were released above Japan, helping to end the world’s bloodiest conflict just weeks later. “Trinity was one of the greatest scientific experiments ever,” said NSRC Senior Historian Alan Carr said. “Los Alamos scientists changed the world forever on that day. Not only was it the dawn of the Atomic Age, but also the beginning of the Lab’s eight decades of cutting-edge science and its national security charge.” To preserve this event, and to continue to learn more about this critical moment in history, the National Security Research Center (NSRC) curates a collection of photographs, films, notes, unclassified artifacts and numerous other materials related to the science of the test. Notably, the collection includes a novel material that formed at the site, trinitite, and artifacts from one of the intriguing scientists present at the test, Enrico Fermi.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

A Partnership between countries that endures today. The British Mission was a part of the Lab from 1943-1945

After 27 months of grueling hours and scientific secrecy amidst the pressure of a mounting death toll and Nazi Germany's own weapons development, it had come to an end. It was time to celebrate. On September 22, 1945, scientists, engineers and their families gathered at Fuller Lodge downtown to celebrate the success of the Los Alamos atomic bomb and the end of World War II. The party was hosted by members of the British Mission and their wives and included food, dancing and a satirical play based on the lighter moments of wartime life in Los Alamos. However, this party was more than just entertainment and a night of festivities, it also represented a partnership between countries that endures today.

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Evaluation of Strain and Exhaustion Limits for Vessels

Design rules for impulsively loaded vessels (ILVs) have been incorporated in Section VIII, Division 3 of the ASME Code since 2019, based upon earlier development of ASME Code Case 2564. These rules are particularly applicable to explosive containment vessels (ECVs) used to fully or partially contain the combustion products of explosives. Uses of these ECVs include containment of suspect luggage at airports, bomb disposal, containment of experiments on explosive devices, and destruction of chemical munitions.

36 MATERIALS SCIENCE↗

The Influence of Environment on Post-Detonation Chemistry and Debris Formation (Abbreviated Final Report: 20-SI-006)

Predicting, responding to, or interpreting the chemical record preserved in debris derived from nuclear events can be challenging due to chemical fractionation. Chemical fractionation is where different species of the evolving radionuclide inventory segregate and/or are lost from the system over the timescales of debris formation. Both historic data and recent research suggest that the interaction and character of the local environment may exert controls on chemical fractionation by influencing the cooling and evolution of the associated fireball as well as the composition of the vapor term and resultant speciation. Prior to this work, an integrated platform permitting dynamic and concurrent consideration of physical and chemical evolution of early time post-detonation event environments did not exist. Our work merged historic data and experimental approaches to support development of a computational framework able to simulate fundamental processes (e.g., entrainment of local environment, oxidation chemistry, and cooling time scales) that may perturb the radionuclide inventory captured in post-detonation debris. Work with historic debris confirmed that entrained environmental material affect debris composition, structure, and radionuclide incorporation. Complementary work utilizing a readily controllable and tunable benchtop setup (a plasma flow reactor) simulated the late cooling of a nuclear fireball (e.g., T < 6000 K) and bounded the sensitivity of actinide speciation and particle size distribution to variations in oxygen concentration and cooling rates. Concurrent laser ablation and laser heating experiments were used to investigate the chemistry and physics of processes occurring in vaporized and/or rapidly heated actinides and other elements in the presence of oxygen. A more computationally efficient microphysical model was developed for predicting and evolving size distributions of particles forming from mixed vapor terms and simulating particle formation processes under a variety of extreme conditions. Continued study of historic nuclear event film confirmed that shockwave data and physics codes agree to within the uncertainty of the data. Good agreement was achieved for thermal emission from an airburst, however the paucity of low-temperature molecular opacity data for mixtures of air, bomb debris, entrained dirt, and water vapor complicate agreement for more elaborate scenarios. A multiphysics code (ALE3D) was modified to bring the necessary physics and chemistry, including these new data and insights, onto a single platform. Code development included improved initialization of large physical systems, modernization of chemistry capabilities, and modifications to enable inclusion of particle transport.

07 ISOTOPE AND RADIATION SOURCES↗

From print to digital: Preserving over 10,000 McKibbin Cards

Collections management staff from the National Security Research Center (NSRC) recently digitized more than 10,000 McKibbin Cards to make them accessible on the Lab’s unclassified network, said NSRC collections management team leader Patricia Cote (WRS-NSRCMS). The cards, named after Dorothy McKibbin, who was known as the gatekeeper of Los Alamos because she was often the first point of contact for new hires, have become symbolic of the Lab when the world’s greatest minds secretly gathered to create the first atomic bomb and end World War II.

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Experimental Set-up for the Study of Chemical Fractionation and Aerosol Dynamics

Experimental investigations of chemical fractionation/phase partition and aerosol dynamics in high-temperature environment were reviewed and discussed. Particle composition and size distribution are the key data for aerosol dynamics predictive model and simulation. However, there were no particle size distribution available from the previous works. Nucleation, condensation, and coagulation are three key physical processes driving the fractionation or phase partition thereby the aerosol dynamics. A new approach was proposed to experimentally observe fractionation/phase partition and provide data for validating the predictive model for aerosol dynamics in the simulation of bomb debris formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Operational and Mission Highlights: A Monthly Summary of Top Achievements October 2022

On Sept. 26, Director Thom Mason signed the Laboratory’s annual assessment of four of the weapons systems in our nation’s nuclear stockpile: the B61 family of bombs and the W76, the W78 and the W88 warheads. Addressed to the secretary of energy, the secretary of defense and the chair of the Nuclear Weapons Council, this letter informs the president of the United States of our confidence that the stockpile remains safe, secure, and effective now and into the future as a result of our dedicated sustainment and modernization efforts.

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Identification of Material Type and Thickness Using Combined X-ray and Fast Neutron Radiography

Material identification (ID) using radiography is a problem that has implicitly existed since the discovery of the X-ray. Since 9-11, this problem has received renewed attention for homeland security applications of the generic, “what is in the box?” type1. Examples of items potentially in the box include: roadside bombs, nuclear weapons, contraband shipments and the like. In these cases, the “what” can include: explosives, projectiles, fissile material, or drugs. Here we investigate the ability of 60Co gamma-rays, 14MeV neutrons, and their combination to tease apart information about density, thickness and atomic number of items in the box. That information subset can be combined with other types of independent information (e.g. neutron and gammaspectroscopy, intelligence, photographs etc.) to assert a more complete picture of what, exactly, is in the box? That more complete information set can form the basis for actions including: remote detonation, evacuations, disablement, detention, search, arrest etc.

36 MATERIALS SCIENCE↗

Nuclear Testing and the Joint Task Force System

During the 1940s, 50s, and early 60s, the United States conducted eight nuclear test operations in the far reaches of the Pacific Ocean. These operations were possible only because of a military command and control organization, the joint task force. Commanded by the Army Navy, and Air Force on a rotating basis, each of the seven JTFs provided the means by which the thousands of ships, planes, material, and personnel were moved over thousands of miles of ocean. The first task force, JTF-1, was created to test the destructive effects of the Fat Man bomb on Naval vessels at Bikini Atoll in the summer of 1946. Commanded by Vice Admiral William “Spike” Blandy, JTF-1 was a purely military operation supported by the MED. Never meant to be a permanent organization, JTF-1 was dissolved soon after completing its mission.

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This St. Patrick’s Day, take a look at “lucky” Lab artifacts from the Manhattan Project

What luck! Tucked inside J. Robert Oppenheimer’s book Bhagavad-Gita is a four-leaf clover. The famed physicist and first Lab director regularly quoted the Hindu scripture, most notably upon witnessing the Trinity test, which was the successful detonation of the first-ever Los Alamos created atomic bomb. Oppenheimer was said to have recalled the line, “Now I am become Death, the destroyer of worlds.” (The quote, though, has been widely misinterpreted.) The clover is taped to what appears to be a calling card from his spouse Kitty and was found inside his copy of the Bhagavad Gita, which was donated to the Lab’s Bradbury Science Museum by private donors Ben and Sara Beck Svetitsky in early 2020. Kitty Oppenheimer was educated as a botanist and biologist, and accompanied her husband to Los Alamos, along with their two children. The family was here in 1943 through the end of World War II in 1945. The book, with the card found inside, makes up one of two of J. Robert Oppenheimer’s personal effects within the Lab’s collections.

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Why the United States? Why NRIC? US Advanced Nuclear Ambitions: History and Future

The United States is the birthplace of modern atomic technology. It was responsible for the development of the first nuclear bomb during World War II as well as subsequent decades of world-leading research into the peaceful applications of the atom for energy generation, medicine, industry, agriculture and home appliances. Today, 30 countries use nuclear power to produce energy with the United States being the largest producer in terms of total gigawatt hours (GWh).

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Did you know the Lab and its first director share a birthday month? A look back at Oppenheimer’s wartime legacy through historical items in our collections

Many birthdays ago, at only 38 years old and with no previous administrative experience, J. Robert Oppenheimer accepted responsibility for a national security mission of unprecedented scale. His charge, handed down by Manhattan Project director General Leslie R. Groves, was to lead a team of the world’s foremost scientific minds in developing the first atomic bomb. Under Oppenheimer’s leadership, a community of over 6,000 scientists, engineers, and other personnel living and working at the top-secret lab in Los Alamos completed their task in only 27 months, delivering the world’s first two atomic weapons to the U.S. military. In honor of what would have been Oppenheimer’s 119th birthday (on April 22), the National Security Research Center remembers his contributions as an administrator and scientist and the scope of his legacy as the first director of the Lab through items in our unclassified collections.

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Why are we still here 80 years later?

The Lab helped end World War II in 1945, but could the Lab survive peace? Join Senior Lab Historian Alan Carr and Historian Nic Lewis as they present “Why we’re still in Business,” examining the role of the Lab once World War II had ended. This presentation, which commemorates the Lab’s 80th anniversary, Carr and Lewis reconsider the popular belief that the Lab nearly ceased to exist after having developed the atomic bombs that helped end war.

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Solving National Security Challenges [Slides]

In 1943, Los Alamos National Laboratory was founded with a single, urgent purpose: to build an atomic bomb. Today, LANL focuses on maintaining a strategic nuclear deterrent, developing technology, and using science and engineering to protect the nation's security. Our workers, facilities, and instruments detect nuclear weapons, facilities, and instruments; promote cooperation and diplomacy; and limit nuclear arms and the spread of nuclear materials, technology, and expertise.

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