Calculations of secondary electron yield of graphene coated copper for vacuum electronic applications

Abstract

The suppression of secondary electron yield (SEY) which can possibly lead to multipactor is an important goal for several applications. Though some techniques have focused on geometric modifications to lower the SEY, the use of graphene coatings as thin as a few monolayers is a promising new development that deserves attention either as a standalone technique or in concert with geometric alterations. Here we report on Monte Carlo based numerical studies of SEY on graphene coated copper with comparisons to recent experimental data. Our predicted values are generally in good agreement with reported measurements. Suppression of the secondary electron yield by as much as 50 percent (over copper) with graphene coating is predicted at energies below 125 eV, and bodes well for multipactor suppression in radio frequency applications.

Electron transmission through suspended graphene membranes measured with a low-voltage gated Si field emitter array

“…The polarity of V Grid could also influence the force experienced by the electrons in the absence of the graphene layer, causing electrons with initial energy lower than 20 eV when emerging from the gate to be stopped. Although graphene has been reported to have low secondary yield, and often used to suppress secondary emission from surfaces, we found that the yields at low energies was significant [27,28]. From the simulations, we have demonstrated that secondary electrons may be the main reason for this increase, it could also be caused by electron-hole pair generation leading to further enhancement in multiple layers [29].…”

Nanoscale characterization of the heterogeneous interfacial oxidation layer of graphene/Cu based on a SEM electron beam induced reduction effect

“…However, graphene has a strong attenuating effect on the emitted secondary electrons, leading to the darker graphene covered area. 39,41–43 In addition, it has been confirmed that the amount of emitted SE can also be affected by the oxidation layer on the Cu surface. 35,44 Therefore, we considered the effects of both the graphene and interfacial oxidation layer on the contrast of the graphene covered area.…”

Recent advances in multipactor physics and mitigation

“…In the Fermilab main injector, diamond-like Carbon coating (DLC) has been found to mitigate multipactor to roughly 2% of that measured in the uncoated stainless steel beampipe [124]. In addition, significant SEY suppression (of almost up to 50% in [125]) has been [117]. (c) The 2D rectangular well geometry assumed in the analytical [116] and the Monte Carlo [117] models.…”