Speaker
Description
Functionalized amorphous carbon (a-C) coatings are being developed to reduce the secondary electron emission yield (SEY) and to control the surface resistance of ceramic supports for the new generation of HL-LHC injection kicker magnets. Pressure spikes observed during high-voltage pulsing of the new injection kicker magnets are attributed to flashovers caused by high electron emission and insufficient draining of surface charge on the alumina supports of the beam-pipe. To address this issue, the alumina supports for the next generation of injection kicker magnets are coated with an a-C film, providing suitable surface resistivity to prevent charge accumulation whilst preserving the insulating function of the supports, together with a low SEY.
This contribution reports on the R&D programme aimed at tuning the resistivity of the a-C films through hydrogen doping while maintaining acceptable SEY performance. Results from the production of a series of 25 coated supports are presented, along with comple-mentary studies carried out to optimise the coating pro-cess for future large-scale production. The potential of these resistive a-C films as alternatives to Ti and TiN coatings for insulating components is also discussed.
| Paper status | Resubmitted proceeding files received and assigned to an editor. Accepted by Submitter. |
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