At the end of 1957, as news of the newly declassified British fusion research circulated in the press, Los Alamos director Norris Bradbury worried that the public might get the impression that the US had been “Sputniked” again. His fear, shared by other scientists involved in research of the Atomic Energy Commission (AEC), shows how the declassification led by the other two leading nations in fusion research, the Soviet Union and the United Kingdom, increased pressure on the United States. This set in motion a round of exchange preceding the Second Geneva Conference on Peaceful Uses of Atomic Energy in 1958. Using untapped archival sources from Russian and British archives, this paper will discuss how declassification, information sharing and reciprocal visits between the Soviet Union and the United Kingdom stimulated a redefinition of the boundaries of secrecy in fusion and how these exchanges expanded and solidified into the 1970s when the Soviets provided their Western allies with key insights into the tokamak principle, which was a milestone in the creation of the Joint European Torus (JET). In this way, the paper aims to contribute to understanding the complex reasons for the East-West exchange during the Cold War.

Historians argue that techno-scientific standardization was a central focus of international scientific organizations throughout the 20th century. Despite its significance, the science diplomacy dimensions of negotiations surrounding international scientific standards - and their profound implications for the circulation of scientific data during the Cold War - remain underexplored. In this historical context, a notable case in point is the establishment of international fundamental physical constants: a set of universal values crucial not only for the advancement of key areas in physics but also for the theoretical unification of diverse scientific frameworks.
Building on this premise, this talk examines the period of the 1950s and 1960s, shedding light on the intricate interplay of interests that led to the adoption of globally standardized values for fundamental physical constants. Two critical aspects of this process are analyzed: the negotiations between physicists and chemists, represented by the International Union of Pure and Applied Physics (IUPAP) and the International Union of Pure and Applied Chemistry (IUPAC), respectively; and the emergence of U.S. leadership in this domain. This leadership was driven by the prominent roles of U.S. experts in international scientific organizations and the significant data compilation efforts spearheaded by the National Academy of Sciences (NAS) and the National Bureau of Standards (NBS).

This paper examines the development of international scientific collaboration on particle accelerators from the mid-1960s to the mid-1970s. During this period, the European Organization for Nuclear Research (CERN) and the Soviet State Committee for the Utilization of Atomic Energy (SCUAE) negotiated agreements to enable the exchange of personnel, scientific instruments, and expertise, as well as joint experiments. The United States, however, was not indifferent to these developments. While initially slow to respond, US authorities eventually supported similar collaboration agreements with the Soviet Union and offered access to the newly established unclassified national accelerator laboratory near Chicago, soon to be known as Fermilab. The paper argues that this strategy reflects a new dimension of “co-produced hegemony” that shaped this particular Cold War period, when East and West sought political détente: American jealousy. It was expressed in the US attempt to assert dominance by controlling Europe’s growing influence in physics. By offering the Soviets a bilateral partnership, the US aimed to shape the future of particle physics research while bypassing Europe. This argument draws on archival sources that uncover the backchannel science diplomacy accompanying the official agreements between CERN, Serpukhov, and Fermilab.

The role of the International Atomic Energy Agency (IAEA) and its technical assistance programs set in place a machinery that mobilized experts on nuclear fields and technologies. The IAEA, established in 1957, became an essential tool for the internationalization and standardization of atomic technologies and for promoting geopolitical influence in the "Third World." The IAEA's technical assistance, particularly in the nuclear field, went beyond nuclear reactors and technologies, extending into agriculture, plague control, food irradiation, and medicine. One of Latin America's first IAEA technical assistance activities was the Mobile Radioisotope Exhibition, which began in Mexico in 1959. It marks the beginning of a series of programs that mobilized people, knowledge, and materialities. The main focus of this paper is on how Mexican physicists leveraged the IAEA's resources through technical assistance programs for their scientific and institutional goals during the 1960s and 1970s, using the opportunities provided by the Agency to further their work in theoretical and experimental physics. The paper will delve into how these scientists navigated within the discourse of "development," the intersection of international scientific collaboration, political interests, and technologies during this period.