Defect depth scanning over the positron implantation profile in aluminum

We present an experimental setup which allows us to measure in a nondestructive way a defect depth profile in light metals and alloys. For this we employ the implantation profile of positrons emitted from the radioactive source (Na-22) which is sensitive probe for open volume defects in crystalline lattice. We demonstrate the setup and the experimental technique using a pure aluminium sample whose surface was damaged after a blasting treatment. A well defined defect profile was detected which coincides well with that established using an alternative technique. The presented setup can be useful for detection of subsurface zones in tribological studies for example.