عنوان المقالة:ﺘﺼﻤﻴﻡ ﺍﻟﻌﺩﺴﺎﺕ ﺍﻟﻤﻐﻨﺎﻁﻴﺴﻴﺔ ﻭﺍﻟﻜﻬﺭﻭﺴﺘﺎﺘﻴﻜﻴﺔ ﺍﻟﺸﻴﺌﻴﺔ ﻟلحزم ﺫﺍﺕ ﺍﻟﻁﺎﻗﺎﺕ ﺍﻟﻤﺘﺩﻨﻴﺔ Design of the Objective Magnetic and Electrostatic Lenses for Low Beam Energies
The design of the objective magnetic and electrostatic lenses with low aberration coefficients at low beam energies is of a considerable interest in various fields of electron spectroscopy. The present research work is concerned with intensive studies and calculations on both types of electron lenses (magnetic and electrostatic) in order to obtain the preferable design of a compound lens. An asymmetrical magnetic electron lens has been designed in conical shape geometry. The study is concerned with a set of asymmetrical two-coaxial overlapping cylinder electrostatic lenses, having different geometries for the outer electrode and length of the electrode gap, respectively. It was found that the geometrical shape of the outer electrode and the length of electrode gap have a clear effect on the electron optical properties of such lenses. It was noticed that the best optical properties occurred when the length of electrode gap (g) equals 5 mm. The results obtained for the objective magnetic lens and the electrostatic lens for the preferable design were compared with the results of the recent published papers. An improvement in the optical properties obtained by the proposed design was noticed to be improved compared to the published results