Details

Autor(en) / Beteiligte

• Michizono, S
• Saito, Y

Titel

Surface discharge and surface potential on alumina rf windows

Ist Teil von

• Vacuum, 2001, Vol.60 (1), p.235-239

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

2001

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• Rf windows are installed at the output port of the klystrons used for the KEKB linac. The breakdown of alumina rf windows is one of the most serious causes of klystron failures. This breakdown is produced by (1) multipactor and (2) surface discharge on the alumina surface. The windows were coated with 1.5 nm-thick TiN films in order to suppress multipactor, and have been used under X-ray irradiation. High-power transmission tests with TiN coated and/or X-ray irradiated alumina ceramics were carried out. In order to evaluate the breakdown phenomena, the secondary electron emission coefficients ( δ) and surface potentials were measured after the tests. The results show that δ was zero at the positively charged area, and recovered to unity after electron-beam irradiation. It is also found that a higher power transmission results in higher surface potentials.