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1、NUCLEARPHYSICSAELSEVIERNuclearPhysicsA605(1996)191-268High-spinspectroscopyofthe142Eu,143Euand144EunucleiM.Piiparinena'b,A.Ataqa,c,j.Blomqvistd,G.B.Hagemanna,B.Herskinda,R.Julinb,S.Juutinenb,A.Lampinenb,j.Nyberga.c,G.Slettena,P.Tikkanene,S.Trrm~inenb,A
2、.Virtanenb,R.WyssdaTheNielsBohrInstitute,TandemAcceleratorLaboratory,DK-4000Roskilde,DenmarkbDepartmentofPhysics,UniversityofJyv?iskylii,FIN-40351Jyviiskylii,FinlandcDepartmentofRadiationSciencesandTheSvedbergLaboratory,S-75121Uppsala,SwedendRoyalInsti
3、tuteofTechnology,PhysicsDepartment,Frescati,S-10405Stockholm,SwedeneAcceleratorLaboratory,UniversityofHelsinki,FIN-O0014Helsinki,FinlandReceived20December1995AbstractHigh-spinlevelschemesofthe142Eu,143EuandJ44Eunucleihavebeeninvestigatedbyin-beamTT-ray
4、spectroscopicmethodsusingtheNORDBALLCompton-suppressedmulti-detectorarray.Thepreviouslyknownschemeshavebeenextendedtoconsiderablyhigherspinandexcitationenergy,uptoI~30,E×~>9MeVin142Eu,I=~,E×=15.6MeVin143Euand1~40,Ex~>16MeVint44Eu.Thelevelschemesarevery
5、complicated,characteristicofsphericalorslightlyoblatenuclei.Also,longcascadesofstretchedE2transitionshavebeenobservedinallthreenuclei.PlungerandDSAMlifetimeresultsdemonstratehighcollectivityvaluesupto~100W.u.(upto~200W.u.in142Eu)intheseE2cascadesandthe
6、yareproposedtorepresentseveralcrossingcollectivebandswiththenucleusattriaxialshapeoff12~0.25and3'~30°.Lowpartsofthelevelschemeshavebeendiscussedwithinthesphericalshellmodel.Below5.5MeVexcitationin~44Euand3.5MeVin143Eupracticallyalltheobservedlevelsarei
7、nterpretedwithshellmodelconfigurationsofrespectivelytwoorfour,andoneorthreequasiparticles.PACS:27.60.+j;25.70.Gh;23.20.Lv;21.60~Cs;21.10.ReKeywords:NUCLEARREACTIONSH°pd(37Cl,3-5n),E=140,160MeV;measuredE~,,I~,(0),),3,-coin,yy(t),RDM,DSAM;142'143'144Eude
8、ducedlevels,J,~r,~',B(MI),B(E2)values.Enrichedtargets,arrayofCompton-suppressedGedetectors,4~"BaF2ball,plunger.ShellmodelandTRScalculations1.IntroductionEuropiumnucleiwithZ=63andN~82,justbelowthesemi-magic146,oA64uu82corenucleus[1]areve
