SUBLINEAR EFFECT IN ELECTRON-EMISSION FROM SOLIDS BOMBARDED WITH SWIFT GOLD CLUSTERS

A sublinear effect in the secondary electron emission from insulating solids under impacts of gold clusters (Au)(n), n = 1-5, with energy E = 33-11000 keV/atom has been observed experimentally using the ARAMIS and Tandem accelerators at Orsay. The effect manifests itself in the d ecrease of the number of emitted electrons per cluster atom with the i ncrease of the number of atoms in the cluster and the projectile energ y. We explain this phenomenon by a mechanism of sweeping-out electrons , which causes a decrease in the number of available electrons in the solid, after the passage of the forward atoms of the cluster through t he atomic layers from which the electrons can be emitted. Calculated a bsolute values of the sublinear effect as well as its dependencies, ba sed on the theory of secondary electron emission, are in agreement wit h the experimental data.