Positron beams

We have two continuous variable-energy positron beams equipped with state-of-the-art detector systems and sample manipulation facilities, and five measurement stations for fast positron spectroscopy. One of the fast positron spectrometers is connected to a cryocooled sample stage of TAMIA and another one is equipped with three detectors (instead of two) for performing experiments in radioactive materials. All the instrumentation has been designed and constructed in-house.

Sample manipulation possibilities during positron experiments include:

Temperature control from 10 K up to 1000 K that allows for defect charge state determination in semiconductors, in-situ annealing experiments in semiconductors and metals, and, e.g., structural analysis of phase transitions in molecular matter.

Monochromatic sample illumination with light wavelength 400 – 2500 nm, allowing for studies of photoionization of defects in semiconductors and, e.g., structural photoresponse in polymers.

Sample biasing, allowing for studies of near-surface Fermi level modification effects in semiconductors as well as positron diffusion.