  On July 16, 1945, the Trinity nuclear test exploded in the desert near
Alamogordo, NM. A variety of new diagnostic experiments were fielded in an
effort to understand the detailed performance of the nuclear device. This
article describes a series of radiochemical experiments that were designed to
measure the efficiency and neutron fluence of the test. These experiments, and
the scientists who led them, laid the foundation of weapons radiochemistry for
decades to come.
