Amal Abd El fattah omer khedr <br/><br/>
Enhancement of the performance of libs technique adopting double pulse configuration for silicon analysis /  
 تحسين اداء تقنية استطياف البلازما المستحثه بالليزر لتحليل السيليكون باستخدام نبضات ثنائية 
Amal Abd El fattah omer khedr ; Supervised Mohamed Abd El Harith Mohamed , Salah Hassab Elnabi , Hisham Imam 
 - Cairo :   Amal Abd El fattah omer khedr ,   2006 
 - 110P :   ill ;   30cm 
<br/><br/>Thesis (M.Sc.) - Cairo University - National Institute Of Laser Enhanced Sciences - Department Of Laser Application In Physics 
<br/><br/> A comparative study between single and double pulse - laser induced breakdown spectroscopy (LIBS) was performed on n - type silicon (111) targetA new mobile double pulse Nd : YAG laser at 1064 nm was used throughout the measurementsThe experiment was carried out in two ambient gases ; air and argon at different pressures of 07 , 470 and 1000 hPa in air and 470 and 1000 hPa in argonThe ambient gas interacts with the laser beam and the plume , several mechanisms are involved in these interactions , such as , plasma shielding , shock wave production and plasma expansionPlasma shielding effect reduces laser - material coupling efficiencyHowever , the induced shock waves increase the coupling efficiency in case of double pulse LIBS 
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<br/><br/><label>Subjects--Index Terms: </label>double pulse silicon