章核物理原子核散射欧内斯特-10课件修正.pptxVIP

Chapter29NuclearPhysics

29.1AtomicnucleusRutherfordscatteringErnestRutherford(8,30,1871-10,19,1937)NewZealandRutherfordwasahumbleman,andmanytheories,instruments,experimentsandpapersthatshouldbeatleastpartiallycreditedtohimare,infact,not)forhisinvestigationsintothedisintegrationoftheelements,andthechemistryofradioactivesubstances.TheNobelPrizeinChemistry1908

5.30MeV,thedistanceisabout42.9fmBackscattering:1/8000“fireda15-inchshellatapieceoftissuepaperanditcamebackandhityou”Rutherfordscattering

electronsof200MeV,l?6.4fmmuonicatoms…Atomicnumber(#ofprotons)NeutronnumberMassnumber=Z+NElementsymbolnuclearprobes:

IsotopesofanelementhavesameZbutdifferentA17/26areradioactive

Shape:Theempiricalformulais

thedensityofnuclearmatterunifiedatomicmassunitu:

themagneticmomentsthebindingenergyof…

themagneticmomentsthebindingenergyof…

MassexcessGenerallyFreeparticles质量过剩

Useofnuclearenergy

?ithasaveryshortrange(?3fm),andissaturate—eachnucleoncannotinteractwithmorethanthefewnucleons;*29.2Nuclearforceandnuclearmodels?nuclearforceisattractivewithrepulsioncore(?0.4fm),whichdominantsCoulombrepulsiontoformthenucleus;?nuclearforceisthestrongestoftheknownforces;

?nuclearforceissamebetweenn-p(chargeindependence),n-n,p-p(chargesymmetry).r~r0=3.1×1017kg/m3not~A(A–1)/2nucleon,notonlyapronoun

Yukawa’sexchangemodelthepionwasdiscoveredin1947withamassof140MeV/c2(~inEMexchangeg)

Similaritycharge—photon—chargemolecule—vanderWaals’force—moleculeQuark—gluon—quarknucleon—nuclearforce—nucleon

LiquidDropmodelbyGeorgeGamowin1928andBohrin1935Appliedtonuclearreaction

anucleoninanucleus,likeanelectroninanatomsomemagicnucleonnumberscometoexplainthatthemorestablenucleiinnatureownspecialZor/andN: