What is a neutron bomb?
Okay, you asked. A neutron bomb is a weapon designed and
constructed specifically to deliver a large(r) dose of radiation
over a broad area to increase the lethality of the weapon without
an increase in blast damage. Be clear that there will be A LOT of
blast damage; it's a nuclear weapon. But the bomb is designed and
constructed to produce more radiation. It's called a neutron bomb
for the reason that there is a gross generation of "extra"
neutrons. Because neutrons have no charge, they penetrate matter
better than a hot knife through butter. Neutrons only minimally
react with electrons (once in a very great while a neutron will
slam into one), so that leaves collision with an atomic nucleus as
their primary means of slowing down. The collisions (skip all the
scattering and recoil stuff) directly ionize materials and/or
create radiation which will in turn ionize stuff. The neutrons do
direct damage to things when colliding, but the secondary effects
do a tremendous amount of damage, too. Organic molecules (the stuff
people are mostly made out of) take heavy damage from the effects
of ionizing radiation. The radiation breaks the covalent bonds of
biochemical substances (that make up living things) in a wholesale
manner. Radiation is the bull in the china shop. The bomb is
actually a fission fusion device. There is a primary stage in which
a conventional chemical explosive is set off. The specially shaped
charges (explosive lenses) are placed precisely around the
fissionable material to drive it together. The shock wave
compresses the heck out of the subcritical masses of, say,
plutonium-239. Begin secondary stage: the fission of the plutonium.
The fissile material goes critical. The chain of fission, neutron
release and further fissions becomes self sustaining. But hold the
phone. Everything is still moving "in" here. Recall the explosive
lenses? The chain goes instantly through criticality to
supercriticality. Neutron production goes through the roof and the
nuclear burn is ramped up. Something like deuterium is added to the
center, and when the fission stage lights up, the heat initiates a
tertiary stage that is fusion. Neutron flux is extremely high, but
materials have been selected for composition and given a geometry
(contour) to allow a whole bunch of the neutrons to escape instead
of building the chain further. That makes for the "enhanced
radiation" part of the "enhanced radiation weapon" as the bomb is
sometimes called. There is a blast like you have never seen.
(Again, it's a nuc; there will be a lot of blast damage.) But
radiation production is maximized. The extra radiation is designed
to slam through things like tank armor. Kill or disable the crew
and you've put the tank out of action. And this radiation is very
lethal to tank crews that may think they've survived the blast
because of the armor of the vehicle. The lethality of the weapon to
those buttoned up inside a tank was the primary thinking behind
development of the bomb. Back in the day, the USSR had NATO way
outgunned in the tank department. The number disadvantage was
severe. We needed an edge. But times have changed. The weapons have
been stricken from the US inventory and are (probably) no longer a
part of strategic planning.