Space- Charge effect in the Design of electron gun using immersion lens under high and low finite magnification condition: Space- Charge effect in the Design of electron gun using immersion lens under high and low finite magnification condition. (2019). مجلة كلية التربية للبنات, 19(2). https://jcoeduw.uobaghdad.edu.iq/index.php/journal/article/view/617