A Theoretical-Based Experimental Approach for Investigating the Charging of Insulators Tareq H. Abbood, Hassan N. Al-Obaidi, Ali Mahdi, Wasan Kadhem, Faten Mousa, et al. Journal of Engineering and Sustainable Development, 2025 A theoretical-based experimental approach has been presented as a simplified tool for investigating the charging of insulators. Throughout this work, the Polyethylene Terephthalate (PET) material is chosen as a case study. The experiment is carried out using the scanning electron microscope (SEM) with a primary energy of 30 keV, an electron current of 1.3 nA, and a working distance of 15 mm. The suggested approach has been initiated by the spacemen-current as the first step. Keeping in mind that this parameter is by default recorded by the SEM machine itself. The total electron yield emission is then determined during the irradiating time in accordance with this. Subsequently, the consuming time, electron-trapped lifetime, trapped electrons, leakage, and displacement currents are evaluated. Results have clearly shown that the knowledge of the spacemen current can be used to provide excellent information to SEM users. Indeed, many of the characteristics factors that define the insulators can be evaluated with no more complicated experimental setup.
Investigation of trapped charges profile for an irradiated insulated material Ali S. Mahdi, Hassan N. Al‐Obaidi, Huda K. Husien Journal of Microscopy, 2022 The process of examining and analysing insulating materials using a scanning electron microscope usually accompanied by an important phenomenon called the mirror effect or charging effects. Such effects arise due to the ability of insulators to trapping charges at the sample surface for a period. The accumulation of charges leads to creating an electric potential that may be strong enough to deflect incident electrons in the same way a convex mirror scatters light. The created potential depends mainly on the charge amount, charges accumulation profile and the way by which the charges arranging themselves. Present work aims at exploring the influences of the charges distribution profile and their arrangements.
Characteristics of probing electrons behavior inside the chamber of scanning electron microscope Imad H. Khaleel, Ali S. Mahdi, Hassan N. Al-Obaidi Journal of Physics Conference Series, 2021 The electron mirror phenomenon has been explored to describe the behavior of a probing electron trajectory inside the chamber of scanning electron microscope (SEM). This investigation has been carried out by means of the modulated mirror plot curve technique. This method is based on expanding sample potential to a multipolar form to detect the actual distribution of the trapped charges. Actually an experimental result is used to guiding results of this work toward the accurate side. Results have shown that the influence of each type of multipolar arrangement (monopole, dipole, quadruple, octopole … etc.) mainly depends on the driving potential.
Approximations of minimum approach distance in electron mirroring phenomena Hassan N. Al-Obaidi, Imad H. Khaleel, Ali S. Mahdi Iop Conference Series Materials Science and Engineering, 2019 The minimum approaches distance of probing electrons in scanning electron microscope has investigated in accordance to mirror effect phenomenon. The analytical expression for such distance is decomposed using the binomial expansion. With aid of resulted expansion, the distribution of trapped electrons within the sample surface has explored. Results have shown that trapped electron distributes with various forms rather an individual one. The domination of any shape is mainly depend on the minimum approaches distance of probing electrons
