Fermium was first discovered in the fallout from the ' Ivy Mike ' nuclear test ( 1 November 1952 ) , the first successful test of a hydrogen bomb . Initial examination of the debris from the explosion had shown the production of a new isotope of plutonium , : this could only have formed by the absorption of six neutrons by a uranium-238 nucleus followed by two β − decays . At the time , the absorption of neutrons by a heavy nucleus was thought to be a rare process , but the identification of raised the possibility that still more neutrons could have been absorbed by the uranium nuclei , leading to new elements
Ivy Mike
Ivy Mike
Fermium