atomic bomb vs physics package

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. 

physics package

noun
  • The part of any equipment which requires advanced knowledge of physics to design; especially the core nuclear components of a nuclear weapon 

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