The detection of all photons emerging from positron-electron annihilations offers several advantages over the standard Doppler broadening techniques. The effective resolution is improved by root2; the signal to noise ratio is improved by a factor of over 1000, enabling the identification of specific elements next to the annihilation site. Finally rare decay modes such as annihilation in flight and 3 photon decays can easily be observed. Here an attempt is made to detect iron gettered at defects engineered by ion implantation at specific depths below the surface. The effects of quantum confinement in CdSe nano particles of 1.8 nm to 4.4 nm in diameter is observed and three photon decays in Si are isolated.