LOS ALAMOS, New Mexico, July 1 -- The U.S. Department of Energy's Los Alamos National Laboratory issued the following news release: Photocathodes that produce electron beams for electron microscopes and advanced accelerators can be refreshed and rebuilt repeatedly without opening the devices that rely on them, provided the electron emitting materials are deposited on single-atom-thick layers of carbon known as graphene, according to a new study published in the journal Applied Physics Letters.   more