Amorphous and Diamond-Like Carbon coatings for SEY reduction of dielectric materials for accelerating structure applications

Multipactor discharges in dielectric accelerating structures are a major limitation on the performance of this otherwise very promising technology for future high energy physics machines and other applications. Multipactor occurs when the Secondary Emission Yield (SEY) of the dielectric material used in accelerating structures is significantly higher than 1. In this work, SEY coefficient versus energy of primary electrons is measured for different dielectric materials used for accelerating structure applications: MgTiO3 (D16) and MgTiO-based conductive ceramic. Furthermore, effect of SEY reduction by means of amorphous Carbon (a-C) and Diamond-Like Carbon (DLC) coatings is investigated experimentally. The results are presented and discussed.