User facilities for Positron Annihilation Spectroscopy (PAS) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR)

Three user dedicated facilities of PAS are built at the Institute of Radiation Physics of HZDR. The first equipment, a mono-energetic slow positron beam with 22Na as positron source, is mainly used for depth dependent Doppler broadening spectroscopy of defects in solids. The other two facilities are driven in connection with a superconducting electron linear accelerator ELBE (Electron Linac for beams with high Brilliance and low Emittance), where the positrons are created by bremsstrahlung and pair production: the Gamma-induced positron annihilation spectroscopy (GiPS) and the pulsed mono-energetic positron beam (MePS).
After an explanation of the fundamentals of PAS, the talk will present an introduction in the set-up and functionality of these three facilities. On the basis of concrete examples the usefulness of the facilities for the investigation of open-volume defects of small size and low concentration in solids will be demonstrated.
At the end of the presentation, a short outline of the procedure for application of PAS beam time will be given.