Electron Yield Measurements of a Carbon-composite Material*

Electron irradiation experiments were conducted to investigate the electron yield and emission properties of an epoxy/carbon-fiber composite material. The structure consists of alternating layers of a carbon fiber weave in an epoxy matrix. We discuss how this nanoscale structure made of both conducting and insulating components with dimensions on the order of electron penetration depths influences the electron yield and emission properties of the material. Secondary, backscatter and emission energy spectra measurements were made in an ultrahigh vacuum electron emission test chamber, with electron beam energies ranging from 15 eV to 30000 eV. Related structural and charging properties have also been investigated by scanning electron microscopy and cathodoluminescence. The emission properties of the composite material are modeled using a nonlinear combination of the two base materials. In various combinations along with effects of surface roughness and morphology.