We have two continuous variable-energy positron beams equipped with state-of-the-art detector systems and sample manipulation facilities and four measurement stations for fast positron spectroscopy, and a pulsed positron beam for positron lifetime measurements with low-energy positrons. 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 and positron diffusion.

Page content by: communications-phys [at] aalto [dot] fi (Department of Physics) | Last updated: 22.01.2016.