Walter Kutschera
Tuesday November 15th 2016 - 7:00 pm ET
Carey Auditorium, Hesburgh Library
Nuclear weapons testing between 1952 and 1963 increased the 14C content in the atmosphere by 100 % over the natural level. After the Nuclear Test Ban Treaty in 1963, this 14C excess rapidly decreased through the CO2 cycle and has reached almost pre-nuclear levels today. During the last 50 years, the hydrosphere and biosphere, including humans, were thus ‘accidentally’ labeled with this rapidly changing 14C. The development of Accelerator Mass Spectrometry (AMS), that is the art of counting 14C atoms ‘one by one’, allows one to trace 14C in ever smaller sample sizes. This led to a variety of unique applications, among which the age determination of cells in the human brain is perhaps the most interesting one. The 14C bomb peak can also be used for forensic studies, to determine the death of a person, to discover frauds in precious pieces of art and illicit trading of ivory. Another important use is the study of the CO2 cycle itself, particularly pertaining to the sequestering of anthropogenic CO2 in ocean and soil. It is somewhat gratifying that the horror of nuclear weapons testing has also created some useful side effects after all.
