Ion Track Technology


Reimar Spohr

PostHeaderIcon Stationary Ion Track Irradiation Facility at GSI


Wide Beam Irradiation

The irradiation system is connected to the beam outlet of a high frequency accelerator and consists of (1) beam shutter, (2) beam widener and (3) sample inlet system.


Up to 20 samples are mounted on a sample holder and inserted into a magazine. The operator selects sample sequence, irradiation angle and fluence. The operator starts the irradiation procedure. The chosen sample is moved into a pumping stage. After reaching the required vacuum, the sample is moved into the irradiation position. The irradiation is started. To monitor the beam intensity during irradiation, the beam passes through a thin carbon foil before hitting the target. The secondary electrons from the carbon foil are used to monitor the relative intensity variations of the ion beam. The absolute intensity is calibrated by counting etched ion tracks in a glass plate. At very low flux density a surface barrier detector is used for counting individual ions that passed through the sample. The beam shutter is activated as soon as the required number of ions is accumulated.


  • Fluence range: 1 ion per sample up to 1 000 000 000 000 ions per square cm.
  • Max sample size: 50 mm x 50 mm x 5 mm.
  • Irradiation angle: 0 to 180 degrees for high fluence irradiations, 90 degrees for single-ion irradiations.


  • Worldwide unique irradiation facility
  • Served hundreds of researchers in the field of ion track technology
  • Fabricated 8 000 membranes with exactly one microchannel of 4.0 (0.1) ┬Ám diameter
  • Coordinated ion track research
  • Coordinated international collaborations on ion track technology


This work was performed at GSI Darmstadt, stimulated by Christoph Schmelzer and furthered by Peter Armbruster, Norbert Angert and Reinhard Neumann. Special thanks to the GSI accelerator team, engineering department, mechanical workshop and electronics workshop.