Stimulated Electron Desorption Studies from Microwave Vacuum Electronics / High Power Microwave Materials
Abstract
This DEPSCoR research examined secondary electron emission (SEE) from thin films and from a warm metal material. Evidence suggests that backscattered electrons as a whole have a preferred scattering direction with a distribution that is dependent on the type of surface treatment. Secondary electron emission was studied from a chemical polished niobium sample during transient cooling from tilde 360 deg K to tilde 293 deg K. It was observed that: (1) "True" secondary electron distributions tend to exhibit a shifted Gaussian-like spatial distribution; (2) a metal structure undergoing transient cooling exhibits some small overall average tendencies on the scattering process; (3) the change in the mean number of scattered electrons seems to increase on average as the metal sample cools; and (4) the emitted backscattered electron cluster appears to be scattered normal to the sample surface for the temperature range considered. A strong AFRL/UNLV collaboration examined four different types of samples. Based on single, pulsed, emission tests, improvements in minimizing secondary electron emission count were observed with the coated copper substrates. Within experimental bounds, secondary electron emission hardening may not take place in all films. Further, the count and distribution are dependent on the primary electron beam's target angle.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 11, 2010
- Accession Number
- ADA515992
Entities
People
- Robert A. Schill Jr.
Organizations
- University of Nevada, Las Vegas