Doppler ­ broadening spectroscopy is a technique that is used to know the properties of matter by means of gamma quanta. The entire energy of an annihilation positron – electron pair includes the energy according to its mass (= 2 x 511 Kev) and kinetic energy corresponding to the motion of the particles causes an energy shift of the annihilation line. The line shape has two parameters S and W parameters,but the W parameter is more sensitive to the chemical surrounding of the annihilation site than the S parameter, because the core electron having high momentum are contributing.
Mainlyin the region of large deviations from the annihilation energy of 511 kev. Both the S and w parameter are sensitive to the concentration and kind of defect.The goal of our work is to investigate the dependence of annihilation parameters on crystal defect the content of Mg atoms in a series of commercial Al – alloys by Doppler broadening technique .
Position parameter like (crystallite size – trapping rate – defect density – dislocation density
Storedenergy).