A key part of
making an atomic bomb in your garage is obtaining a suitable
neutron deflector. The
neutron deflector should surround the
fissionable material and be comprised solely of
uranium-238. Not only is
U-238 non-fissionable, it also has the unique ability to reflect
neutrons back to their source.
The U-238 neutron deflector serves 2 purposes:
- In a uranium bomb, the neutron deflector serves as a safeguard to keep an accidental supercritical
mass from occurring by bouncing the stray neutrons from the `bullet' counterpart of the uranium mass away from the greater mass below it (and vice-versa).
-
In a plutonium bomb, the neutron deflector actually helps the wedges of plutonium retain their neutrons by reflecting the stray particles back into the center of the assembly.