neutron bomb vs thermonuclear

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. 

thermonuclear

noun
  • A thermonuclear weapon. 

adj
  • Of, or relating to the use of atomic weapons based on such fusion, especially as distinguished from those based on fission. 

  • Of, or relating to the fusion of atomic nuclei at high temperatures. 

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