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1、蘭州大學(xué)博士研究生學(xué)位論文密度分布模型計算所得結(jié)果均小于氘密度分布為常數(shù)時的計算結(jié)果。研究發(fā)現(xiàn)在Yb,Pd材料中D(d,p)T反應(yīng)具有溫度效應(yīng),即在相同彈核能量條件下,質(zhì)子的產(chǎn)額隨溫度升高而降低。這項工作首次研究了氘密度深度分布對屏蔽勢能推導(dǎo)帶來的影響,提出有關(guān)氘分布模型并加以驗證,運用模型重新計算了屏蔽勢能。盡管如此,實驗數(shù)據(jù)處理中還有不確定性:一是氘在相關(guān)介質(zhì)中的阻止本領(lǐng),在如此低的能區(qū)還沒有阻止本領(lǐng)的實驗數(shù)據(jù),只能采用理論編評的結(jié)果(用SRIM計算):二是反應(yīng)截面也是采用理論推導(dǎo)結(jié)果,需要有更高精度的計算;三是文中所提出的氘靶核密度分布模型較為粗糙,會給計算結(jié)果帶來一定的誤
2、差,需要進一步完善。關(guān)鍵詞:電子屏蔽效應(yīng)含氘金屬靶密度深度分布AbstractAlastingtopicinnuclearastrophysicsisthescreeningofthenuclearCoulombpotentialduetotheatomicelectronsinlaboratorynuclearphysicsexperimentswhichenhancestheexperimentalreactioncross-sectionsatlowenergiesrelativetothebarenucleus.Thecrosssectionsofnuclearfusio
3、nreaction盯(E)inenergyregionfarbelowtheCoulombbarrierisroughlyrepresentedbytheGamowfac-tor,anddropsexponentiallywithdecreasingprojectileenergy,whicharehardtobemeasuredaccuratelyandareextrapolatedfromthedataathigherenergiescustomarily.TheCoulombpotentialofthetargetnucleusandprojectiletheoret—ic
4、allycalculatedfrombarenucleistates.However,thetargetnucleistudiedinlaboratoryareusuallyintheformofatomsormolecules,SOthattheCoulombbarrieriseffectivelyreducedbothinheightandradialextension.Asaresult,thecorrespondingcrosssectionsarehigherthanwouldbethecaseforbarenuclei.Theenhancedcrosssectiona
5、s(E)isexpressedasas(E)=ab(E+玩)withanelectronscreeningpotential玩,andab(E)isthecrosssectionforbarenucleus.TheD(d,p)Treactionsindifferentmaterialsinsub-lowenergyregionhavebeenstudied.Thoughanalysismethodsforthe鞏ofD(d,p)Treactioninmetalenvironmentweredifferent,theywereallbasedonanassumptionofasta
6、bleandhomogeneousdeuterondensitydistribution.However,thedeuteronatomissmallerthananymetalatomsanditsutmosthi【ghmobilitynlakestheassump-tiondoubtful.Therefore,onecansupposeneitherastablenorahomogeneousdeuterondensitydistributionwhichisrequiredbythestandardanalysismethod.Soaroughmodelofdeuteron
7、sdensitydistributionisintroduced.TheexperimentwasperformedattheLaboratoryofNuclearScience,To-hokuUniversity.ThedeuteratedthicktargetsusedinthisworkareBe,A1,蘭州大學(xué)博士研究生學(xué)位論文Dy,YbandZrmetal,respectively.Theprojectileenergyrangeis5keV--。10keV(CMS),