Continuous Versus Average Cross Section
Cross sections depend strongly on the incoming particle speed. In the case of a beam with multiple particle speeds, the reaction rate R is integrated over the whole range of energy:
Where σ(E) is the continuous cross section, Φ(E) the differential flux and N the target atom density.
In order to obtain a formulation equivalent to the mono energetic case, an average cross section is defined:
Where Φ= Φ(E) dE is the integral flux.
Using the definition of the integral flux Φ and the average cross section σ, the same formulation as before is found:
Read more about this topic: Neutron Cross Section
Famous quotes containing the words continuous, average, cross and/or section:
“We read poetry because the poets, like ourselves, have been haunted by the inescapable tyranny of time and death; have suffered the pain of loss, and the more wearing, continuous pain of frustration and failure; and have had moods of unlooked-for release and peace. They have known and watched in themselves and others.”
—Elizabeth Drew (1887–1965)
“That’s one thing I like about Hollywood. The writer is there revealed in his ultimate corruption. He asks no praise, because his praise comes to him in the form of a salary check. In Hollywood the average writer is not young, not honest, not brave, and a bit overdressed. But he is darn good company, which book writers as a rule are not. He is better than what he writes. Most book writers are not as good.”
—Raymond Chandler (1888–1959)
“Life is a bridge. Cross over it, but build no house on it.”
—Indian proverb, quoted in Bruce Chatwin, The Songlines, ch. 30, “From the Notebooks” (1987)
“To look at the cross-section of any plan of a big city is to look at something like the section of a fibrous tumor.”
—Frank Lloyd Wright (1869–1959)