辐射保护导论

Radiationiseverywhere.Inthisbook，weareconcernedwithionizingradiation，i.e.radiationthatcanionizeordinaryatoms.Translatedintoenergiesthiscorrespondstoa，p，oryrayswithenergieslargerthan，say，30eV.Almosteverythingisradioactive.Radiationemergesfromthesoil，itisintheair，andourplanetisconstantlybombardedwithenergeticcosmicradiation.Eventhehumanbodyisradioactive:about9000decaysofunstablenucleioccurpersecondinthehumanbody.IntheearlydaysoftheEarth，whenourplanetwasformedfromthedebrisoftheproto-solarsystem，theradiationlevelwasevenhigher.Onecanassumethattheoriginanddevelopmentoflifemighthavebeenpositivelyinfluencedbyionizingradiation.