Contributions to the knowledge of excess noise

This paper describes measurements on the noise behavior of a long, magnetically focused electron beam with a convergent Pierce-type electron gun having a shielded cathode. It is found that the excess noise phenomenon is initiated by a scallop-beam amplification and is essentially dependent on the nonlaminarity of electron flow in the beam. The beam reaches a state of high thermal equilibrium which may be caused by strong electron-electron interaction. An estimation shows that this should be theoreticaly possible.