最新培训课件 X射线荧光分析导论-药学医学精品资料.ppt

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1、最新培训课件X射线荧光分析导论-药学医学精品资料电子波谱1Hz-1kHz1kHz-1014Hz1014Hz-1015Hz1015Hz-1021Hz超低频率电磁波无线电波微波红外线可见光伽马射线紫外线LowenergyHighenergyX射线Theory入射X射线轰击原子的内层电子，如果能量大于它的吸收边，该内层电子被驱逐出整个原子（整个原子处于高能态，即激发态）。较高能级的电子跃迁、补充空穴，整个原子处于低能态，即基态。由高能态转化为低能态，释放能量。ΔE=Eh-El.能量将以X射线的释放，产生X射线荧光。SideWindowX-RayT

2、ubeBeWindowSiliconeInsulationGlassEnvelopeFilamentElectronbeamTarget(Ti,Ag,Rh,etc.)CopperAnodeHVLeadRadioisotopesIsotopeFe-55Cm-244Cd-109Am-241Co-57Energy(keV)5.914.3,18.322,8859.5122Elements(K-lines)Al–VTi-BrFe-MoRu-ErBa-UElements(L-lines)Br-II-PbYb-PuNonenoneWhileisotope

3、shavefallenoutoffavortheyarestillusefulformanygaugingapplications.OtherSourcesSeveralotherradiationsourcesarecapableofexcitingmaterialtoproducex-rayfluorescencesuitableformaterialanalysis.ScanningElectronMicroscopes(SEM)–Electronbeamsexcitethesampleandproducex-rays.ManySEM

4、’sareequippedwithanEDXdetectorforperformingelementalanalysisSynchotrons-ThesebrightlightsourcesaresuitableforresearchandverysophisticatedXRFanalysis.PositronsandotherParticleBeams–Allhighenergyparticlesbeamsionizematerialssuchthattheygiveoffx-rays.PIXEisthemostcommonpartic

5、lebeamtechniqueafterSEM.SourceModifiersSeveralDevicesareusedtomodifytheshapeorintensityofthesourcespectrumorthebeamshapeSourceFiltersSecondaryTargetsPolarizingTargetsCollimatorsFocusingOpticsSourceFiltersFiltersperformoneoftwofunctionsBackgroundReductionImprovedFluorescenc

6、eDetectorX-RaySourceSourceFilterFilterTransmissionCurve%TRANSMITTEDENERGYLowenergyx-raysareabsorbedAbsorptionEdgeX-raysabovetheabsorptionedgeenergyareabsorbedVeryhighenergyx-raysaretransmittedTiCrTitaniumFiltertransmissioncurveThetransmissioncurveshowsthepartsofthesourcesp

7、ectrumaretransmittedandthosethatareabsorbedFilterFluorescenceMethodENERGY(keV)TargetpeakWithZnSourcefilterFeRegionContinuumRadiationThefilterfluorescencemethoddecreasesthebackgroundandimprovesthefluorescenceyieldwithoutrequiringhugeamountsofextrapower.FilterAbsorptionMetho

8、dENERGY(keV)TargetpeakWithTiSourcefilterFeRegionContinuumRadiationThefilterabsorptionMeth