Because of its relevance for negative hydrogen ion sources, the change in s
econdary electron emission with the adsorption of Cs on Cu was studied. Pro
perly prepared disks of oxygen free high conductivity (OFHC) copper yielded
a maximum secondary electron emission delta(max) = 1.54 +/- 3%. The deposi
tion of = 0.5 monolayer of Cs resulted in delta(max) = 3.40 +/- 3%. (C) 199
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