Dosimetry characterization and the evaluation of kinetics parameters of trapping states of Mg-doped ZnO phosphors synthesized by Sol-Gel technique. The thermoluminescence response of Mg-doped ZnO samples showed a linear response when exposed to X-ray radiation and the optimum annealing condition was 400oC/4h for the three concentrations. A broad-shaped TL glow curve with an upper bound of 270 °C, which shifts to lower temperatures with increasing dose, indicating that general order (GO) kinetics thermoluminescence processes are involved. We conclude that the ZnO doped Mg phosphors under study are promises to develop dosimeters for high radiation dose measurements. Kinetic parameters, such as activation energy (E), frequency factor (s), and order of kinematic order (b), were estimated by the Glow Curve Deconvolution (GCD) method. ZnO:Mg phosphor has a great potential as a dosimeter for monitoring in the fields of ionizing radiation. arabic 9 English 49
Fawzeia Khamis, , (1-2021)

In this paper, considers a solution of Maxwell's curl equations by using the finite-difference time-domain (FDTD) method. We simulated electromagnetic waves propagation in free space. The electric and magnetic fields generated in two cases to make a comparison between the models. All models were computed using the same parameters. This study showed that the intensities of the fields affected when adding three excited sources pointed in three locations. However, it was noted that three sources placed in the same location improved the distributions of the fields. Therefore, this difference in excitation position leads to change the image intensity distribution. arabic 7 English 43
Adel G Diyaf, Sedig S. Farhat(4-2017)

تم دراسة المرنانات غير المستقرة في المنظومة الليزريه بشكل عام والتركيز على أحد المشاكل التي يواجهها هذا النوع من المرنانات وهي تأتيرات الحيود. فرغم ان هذه الظاهرة تعتبرالوسيله التي يخرج عن طريقها الشعاع من المنظومه الليزريه الا انها تسبب في فقدا كبيرا في قدرة الشعاع الليزري الخارج . احدي الطرق المقترحه للتقليل من تاتيرات الحيود السلبيه في هذه الحاله هو احدات تدرج في المرآه , فقد تم في هذا البحث مقارنة نتائج متقاربه وعليه تم استنباط معادلة خاصه بالحيود عبر مرآة بتدرجين وحساب القيمة الذاتية للشعاع الليزري الخارج وتحدي مدي التحسن في التقليل من الخسارة الناتجه من خلال التغير في قيمة عدد فرنيل وذلك بمقارنة العلاقات البيانية لمرآة عادية ومرآة بتدريج واحد وبتدرجين للمرنان نفسه , و تم أيضا دراسة تاثير القيمة الذاتية بعرض الدرجة في المرآة وعرض المنحنيات الخاصة بها . Abstract Unstable resonators in laser systems have been studied in general and the focus was on one of the problem facing this type of resonators namely the effect of diffraction .although diffraction Is the mean to get the laser rays out of the system, it causes major loss of power in the output If it is treated adequately. One of the suggested method to reduce the negative effect of diffraction is to make a gradual step on the output mirror. a comparison has been made between the results for a single step mirror with result from previous study . the two results agreed with each other to an acceptable range . an equation for a two-step mirror was derived and the Eigen Values of the outgoing laser beam were calculated . the amount of improvement in the output power was calculated by changing the value of Fresnel number and comparing the situation for an ordinary mirror , single step mirror and two-step mirror. The results show good improvement for the two-step mirror. also the dependence of the step with on the eigen value was studied. We can conclude from the current work that by introducing certain step width specific width could improve the output power from unstable resonators by minimizing the negative diffraction effect. The amount of improvement seems to increase with increasing number of steps. For future work we suggest that more exact methods to calculate the eigen values, such as proni method, should be tried and the effect of the output mirror tilt must be taken into account.
سهير محمود احمد ابو حجر (2001)