On Schottky Noise and Shot Noise

Abstract

Schottky noise is a common term widely acknowledged by the community of accelerators, especially of circular machines. It is referred to the incoherent signal arising from the circulating charged particles in the accelerator. The noise is named after W. Schottky, who first discovered a then new type of noises in direct electric current and called it shot noise himself. Because of this, the Schottky noise is considered as an alias for the shot noise in accelerator literatures. But is it really so? In this essay I compare the two noises side-by-side by formulas and argue that even though they arise from the same discrete nature of charge carriers, the noise spectral patterns are inherently distinct, whereby the synonymity of these two terms is questionable.