Hisato Yamaguchi

It has been argued that the isolation of monolayer graphene is among the most important discoveries in the last half century. Graphene has led to new thinking about how to address persistent challenges faced by traditional material systems. A long-standing problem faced by the particle accelerator community is that of limited lifetime of electron sources. These sources launch the electron beam which is bunched and accelerated to high energies for many different applications, ranging from next generation user facilities for discovery science to directed energy systems for defense and environmental needs. Addressing limited lifetime of electron sources is a complicated problem, but we have made progress toward developing a methodology to use multiple graphene layers as a monolayer ruggedizing shield which does not appreciably disrupt photoemission but does provide a barrier isolation which could increase cathode lifetime. We present key results to date which enable graphene to function as a monolayer shield for sensitive photocathode films.