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1、中國科學(xué)技術(shù)大學(xué)博士學(xué)位論文正電子湮沒多參數(shù)測量系統(tǒng)研制姓名：孔偉申請學(xué)位級別：博士專業(yè)：粒子物理與原子核物理指導(dǎo)教師：周先意;葉邦角20040501lFIUr湮沒多參數(shù)測量系統(tǒng)Ⅲ制中閏科學(xué)技術(shù)人學(xué)悻簞l-學(xué)世論之作為研究缺陷類型的例子。第四章主要介糾了壽命-動量關(guān)聯(lián)測姑系統(tǒng)，井詳細(xì)討論了計數(shù)率對能譜譜形的影響以及對麻的改進(jìn)上作，測量的實例是碳納米管材料。互I!￡塑鯊蘭莖塑型墅墨竺業(yè)型!旦型蘭絲查苧蘭堡!：蘭絲笙墨AbstractThePAS(PositronAnnihilationSpectroscopy)，asaco
2、mmonmethodtostudythestructureofmaterials．hasitsinbornadvantageinthestudyofdefectsinsolids．‘Originally，thePASincludesPAL(positronannihilationlifetimespectroscopy)，DEBS(Dopplerbroadeningenergyspectrum，orDBAR，DopplerBroadeningAnnihilationRadiation)，ACAR(Angularcorre
3、lationofannihilationradiation)．AfterthegreatadvancingofPASin1960s’，researchersdon’tfeelthesetechniquesareenough，andtheybegintofindothermethodstostudythematerialswithpositron．Aftertheireffort，newtechniquesappeared，suchas2D·DBAR(2-DetectorDopplerBroadeningAnnihilat
4、ionRadiation)，AMOC(Age—MomentumCoincide，AMOC)，PAES(PositronAnnihilationinducedAugerElectronSpectroscopy)，etc．Becauseofthedifficultytorealizethesesystems，thereislittleattentiononthesetechniquesintheirfirstyears．In1990’s，aftertheinprovementoftheelectronictechnique，
5、manysystemsarerealized，andplayimportantrolesinstudyofdefectandthestructureofmaterials．Inthesemethods，themulti—parametermeasurementsystem，suchas2D·DBARandAMOC，cangetabundantinformationinmaterials．The2D—DBARisusedinthefieldofelementalspecificityandstudyofthechemica
6、lenvironmentintheannihilationsite，andAMOCcanbeusedtostudytheformationandannihilationofpositronium，thetranslationofdifferentstate．Thesetwomethodscanhelpustodiscovermoredetailsinmaterials．DigitaltechnologyisbeWidelyusedinnuclearphysicsandpaticlephysics．Today,weCall
7、processdigitalpulsedirectlyowetotheimprovementofdigitaltechnology．Thesedigitalmethods，especiallythedCFD，areusedinPALandTOFspectrometersuccessfully．ItwillbenefitPAStousemulti—parametermeasurementanddigitaltechnology．Anew2D·DBARsystemissetupforadvancedstudyindefect
8、sofmaterialsandanoriginalmodelofAMOCissetupdependingontheexperienceofbuilding2D—DBARsystemThedifferencebetweenthesetwosystemsandsomeother2D·DBARandAMOCsystemsi
