Environmental influence on MM-type dispenser cathodes used in VED's and propulsion systems

In the present work the basic functional concept of the TED hollow cathode neutralizer and the Qualification philosophy for vacuum electronic cathodes will be introduced briefly. Then the results of the twofold Qualification program of the hollow cathode neutralizer will be presented in more detail. Especially the influence of the environment on the neutraliser was investigated and, it was found that the TED hollow cathode neutralizer is capable of enduring the exposition to significant amounts of humidity for several times without performance degradation. Additionally, it could be demonstrated, that the plasma operation of the neutralizer serves as proper means for the regeneration of a poisoned cathode surface.