atomic bomb vs neutron bomb

atomic bomb

noun
  • A nuclear weapon that obtains its destructive energy from nuclear fission. 

  • The possession of one or more atomic bombs; the ability to launch a nuclear attack. 

neutron bomb

noun
  • An atomic bomb that produces a greater amount of neutrons, and a lesser amount of blast; the intention being to create equal lethal neutron radiation and blast radii which increases the effectiveness of the weapon against armour while reducing collateral damage. 

How often have the words atomic bomb and neutron bomb occurred in a corpus of books? (source: Google Ngram Viewer )