Anode ray

They were first observed in Crookes tubes during experiments by the German scientist Eugen Goldstein, in 1886.

[1] Later work on anode rays by Wilhelm Wien and J. J. Thomson led to the development of mass spectrometry.

These collide with atoms of the gas, knocking electrons off them and creating more positive ions.

By the time they reach the cathode, the ions have been accelerated to a sufficient speed such that when they collide with other atoms or molecules in the gas they excite the species to a higher energy level.

[2][3] Application of a sufficiently high electrical potential creates alkali or alkaline earth ions and their emission is most brightly visible at the anode.