work function of yttrium (Y) and at the same time preserves all of the advantages of copper
(Cu) when inserted into a radio-frequency gun. The configuration consists of a disk of Y
covered by a coating of Cu deposited using the pulsed laser ablation technique, while
masking the central part of the Y disk by a shield making the photoemission directly from the
Y bulk possible. The new device was characterised by scanning electron microscopy to …