پديد آورنده :
غلامي ناشر، سعيد
عنوان :
بررسي تغييرات ايجاد شده در ساختار نقص ها در نمونه هاي مسي در اثر دماي باز پخت با استفاده از روش طيف نمايي طول عمر پوزيترون
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
فيزيك هسته اي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك
صفحه شمار :
ده،110ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
احمد شيراني
استاد مشاور :
پرويز كاملي
توصيفگر ها :
سيستم سريع/كند , قدرت تفكيك زماني , نرم افزار LT9-2
تاريخ نمايه سازي :
15/12/91
استاد داور :
محمد حسن علامت ساز،اكبر پروازيان
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
000Investigation of changes produced in the structure of defects in copper samples during the annealing temperature using Positron Lifetime Spectroscopy Saeid gholame saeidgolame@yhoo com December 31 2012 Department of physics Department of Physics Isfahan University of Technology Isfahan Iran Degree M Sc language FarsiDr Ahmad Shirani Mail shirani@cc iut ac irAbstractPositron lifetime spectroscopy is a reasonably accurate method to study defects in materials In thismethod the time difference between emission of the 1 274 MeV gamma ray which is emittedSimultaneous with positron from a 22Na source and the 0 511 MeV gamma ray which is emitted as aresult of positron annihilation in the sample surrounding the source is measured This time difference isthe positron lifetime in the sample which is directly related to the size and the number of defects in thesample in which the positron has been annihilated In addition the structure of defects in a metal sampleis changed with annealing temperature and this effect can also be investigated by positron lifetimemeasurement In this work reasonably good time resolving power was first determined for the systemusing a 60Co source and then a 22Na source was placed between two copper samples and positron lifetimewas measured at room temperature Copper samples were then annealed at 150OC to 650OC annealingtemperatures and positron lifetimes were also measured for these samples and then analyzed using theLT9 2 software The results obtained show that the average lifetime first decreases with increasingtemperature due to disappearance of some defects in the samples and then increase due to appearance ofsome new defects for example creation of grain boundaries in the sample Keyword Positron Life time Spectroscopy 22Na Source coincidence system time resolution vacancy defect in samples positronium annealing temperature
استاد راهنما :
احمد شيراني
استاد مشاور :
پرويز كاملي
استاد داور :
محمد حسن علامت ساز،اكبر پروازيان
