>>11550100not like a physics lecture, but stuff like
"nium bomb to failure that summer. More than a year previously Glenn
Sea borg had warned that the isotope Pu240 might form along with desir
able Pu239 when uranium was irradiated to make plutonium. Pu240, an
even-numbered isotope, was likely to exhibit a much higher rate of sponta
neous fission than Pu239. The plutonium samples Emilio Segre had studied
at his isolated log-cabin laboratory fissioned spontaneously at acceptable
rates. They had been transmuted from uranium in one of the Berkeley cy
clotrons. U238 needed one neutron to transmute to Pu239; for Pu240 it re
quired two, and far more neutrons bombarded the uranium slugs cooking
in the X- I O pile than a cyclotron could generate. When Segre measured the"
