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Abstract

Transmission of microwave radiation at the lower hybrid frequency may induce multipactor breakdown in the coupling structure of a tokamak machine. To increase the R.F. power throughput to a plasma, secondary electron emission on the waveguide walls and subsequent electron multiplication which cause multipactor breakdown effect must be reduced. In this work measurements of secondary electron yields #Gs of two kinds of coatings (graphite, TiC) on S.S. were performed as a function of primary beam energies (100 eV; 1.1 keV). Also uncoated stainless steel was measured. Results show sigma to have a typical energy dependence, with a peak occurring at 200 to 300 eV for normal electron beam incidence. The graphite and TiC coatings after surface treatment give sigma4 m4a4x < 1, which allows to reduce multipacting in the waveguide.

Additional information

Authors: FRANCONI E CENTRO RICERCHE ENERGIA FRASCATI (ITALY), CENTRO RICERCHE ENERGIA FRASCATI (ITALY)
Bibliographic Reference: 9TH INTERNATIONAL VACUUM CONGRESS AND V INTERNATIONAL CONFERENCE ON SOLID SURFACES, MADRID (SPAIN), SEPT. 26 - OCT. 1, 1983 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31343 ORA
Availability: Can be ordered online
Record Number: 1989122066800 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: en