Kinetic Secondary Electron Emission from Solids by Fast Incident Electrons
Comprehensive Exam
3:30 pm –
5:00 pm
Jorgensen Hall Room: 145
Target Audiences:
Contact:
Physics Department, (402) 472-2770, paoffice2@unl.edu
William Newman will present his colloquium exam topic, “Kinetic Secondary Electron Emission from Solids by Fast Incident Electrons” in person.
Abstract: The study of kinematic secondary electron emission from solids by electron bombardment spans well over a century with experimental observations and preliminary models established around the mid 20th century. This presentation will outline the observed behavior of the secondary electron yield and how it varies with the energy of the primary electron, the material of secondary emitter, and the surface properties of the emitter. These observations will be tied to a few notable semi-empirical models developed to gain physical insight into the process and provide a method of prediction and comparison. In addition to the general understanding of the phenomenon, the application of secondary electron emission in scanning electron microscopes and photomultiplier tubes is incorporated as well as a discussion on the unwanted secondary electron emission side effects in modern plasma and accelerator applications. The secondary electron effects in the mentioned applications are strongly dependent on the surface of the emitter, and recent studies on these effects will be highlighted to demonstrate the current relevance of this phenomenon to modern physics and engineering.
Abstract: The study of kinematic secondary electron emission from solids by electron bombardment spans well over a century with experimental observations and preliminary models established around the mid 20th century. This presentation will outline the observed behavior of the secondary electron yield and how it varies with the energy of the primary electron, the material of secondary emitter, and the surface properties of the emitter. These observations will be tied to a few notable semi-empirical models developed to gain physical insight into the process and provide a method of prediction and comparison. In addition to the general understanding of the phenomenon, the application of secondary electron emission in scanning electron microscopes and photomultiplier tubes is incorporated as well as a discussion on the unwanted secondary electron emission side effects in modern plasma and accelerator applications. The secondary electron effects in the mentioned applications are strongly dependent on the surface of the emitter, and recent studies on these effects will be highlighted to demonstrate the current relevance of this phenomenon to modern physics and engineering.