Cross‐section measurements made with neutrons from a nuclear detonation

Abstract

Ever since the first nuclear detonation near Alamogordo, N. M., on July 16, 1945, there has been much speculation, and a few full‐scale experiments, on the use of such detonations as a source of neutrons for measurements using time‐of‐flight definition of neutron energy. Although these time‐of‐flight experiments are in principle quite simple, they had to await the solution of a myriad of unusual engineering problems. When the United States and other nations agreed in 1963 to discontinue atmospheric testing of nuclear weapons, the Atomic Energy Commission invested considerable effort in the development of techniques for underground testing. In the course of this work, vacuum flight paths hundreds of meters long were used from time to time. They were quite straight, with antiscattering baffles and provision for closure to contain bomb debris and radioactive gases. The dirt fill around the pipe provided excellent shielding for the neutron collimator, and it was natural at this stage of development to consider the possibility of cross‐section measurements.