ABSOLUTE LUMINESCENCE EFFICIENCY OF ION-BOMBARDED SOLID ARGON

We have directly measured the absolute efficiency of the 9.8-eV M-band luminescence from the decay of Ar-2 excimers in solid; Ar bombarded by 1.5-MeV He+ and 10-50-keV H+ ions. About 54% of the electronic ener gy deposited by the projectiles is converted to 9.8-eV luminescence en ergy, or about 5.5 photons per 100-eV deposited. The efficiency is als o found to be independent of ion and ion energy for those tested over a range of stopping cross sections from 6.5 to 400 eV/(10(15) atoms/cm (2)). This work clearly establishes the M band as the major relaxation pathway, for electronically deposited energy in solid Ar, a pathway t hat is an important source of radiation damage and sputtering and whic h can be affected by electron emission.