The conversion from megatons to joules is 1 megaton = 4.2x10^15 joules. This
is from a textbook on nuclear physics, so I believe its accurate. Since
E=mc^2, 1kg of antimatter annihilating with 1kg of matter puts out the same
energy as a 43 megaton explosion. Thus the 1cc chunks of anti-lead (about 10g)
are equivalent to a 430 kiloton bomb. The cubic meter would be equivalent to
a 430 gigaton bomb. Most of this energy is released in the form of HARD gamma
rays, so even without the impact, the target is going to be really toasty.
Ted Baltz
[email removed]