Secondary emission in physics is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles. The primary particles are often charged particles like electrons or ions. If the secondary particles are electrons, the effect is termed secondary electron emission. In this case, the number of secondary electrons emitted per incident particle is called secondary emission yield. If the secondary particles are ions, the effect is termed secondary ion emission.
Famous quotes containing the words secondary and/or emission:
“Words are always getting conventionalized to some secondary meaning. It is one of the works of poetry to take the truants in custody and bring them back to their right senses.”
—William Butler Yeats (1865–1939)
“Approximately 80% of our air pollution stems from hydrocarbons released by vegetation, so let’s not go overboard in setting and enforcing tough emission standards from man-made sources.”
—Ronald Reagan (b. 1911)