Applications of positron annihilation spectroscopy

Positron annihilation spectroscopy techniques are well established nuclear techniques with applications which nowadays range from structural investigations of materials to investigations of biological samples and medical imaging. They have extensively been used more than thirty years, but with constant improvements in measuring methods and with new applications, especially in investigations of technologically important materials. In standard positron annihilation spectroscopy suitable positron source is used, and techniques include positron lifetime measurements, Doppler broadening spectroscopy and angular correlation measurements. In the recent times slow positron beams combined with these techniques are applied as well, providing depth-profiling of the samples. We are going to present digitized positron lifetime system and a novel system for simultaneous positron lifetime and Doppler broadening spectroscopy developed at the Department of Physics in Zagreb and measurements with these systems using 22Na as positron source. Their advantages compared to conventional systems and further development of the positron annihilation spectroscopy techniques by employing signal digitizers in multidetector systems and possible applications will be described. (author)