bomb pulse
n.— «Because of atmospheric testing of nuclear bombs between 1945 and 1960, the atmosphere received a sharp spike of carbon-14, commonly called the “bomb pulse,” that has been declining to normal levels as excess carbon-14 has been absorbed into the ocean. The yearly amount of carbon-14 has been carefully monitored and is well known.» —“Study: Radioactive eyes don’t lie” Pittsburgh Post-Gazette (Pennsylvania) Feb. 23, 2008. (source: Double-Tongued Dictionary)