RADIOACTIVE ION-IMPLANTATION FOR WEAR STUDIES

Direct implantation of radioactive ions such as Be-7 or Na-22 into a s urface allows precise, sensitive wear measurements by monitoring the g amma-ray activity worn away. This technique complements and supplement s the more standard surface-layer activation technique and offers seve ral novel advantages: It is independent of the Z of the object being s tudied, thus allowing wear studies on low-Z materials such as plastics and ceramics. Also, the beam of implanted ions is considerably less i ntense (approximate to 10(-5)) than the beam used for activation, maki ng it less likely that the surface to be studied is damaged by the bea m. We present our techniques for producing the implantation beam by fr agmentation of heavy-ion cyclotron beams, and we describe experiments demonstrating that the surface is indeed not significantly damaged by the implantation process.