The Trek experiments

Trek is an experiment designed to measure the isotopic and elemental composition of the galactic cosmic rays (GCR). The Trek detectors were placed on board the Russian space station Mir in 1991. They consist of two detectors: the first, smaller detector was deployed on an inside wall of the living quarters of Mir, and is designed to measure the isotopic composition of iron-group elements. The second, larger detector was placed on the outside of Mir, and is designed to measure the elemental composition of ultraheavy elements with Z > 50. We describe the astrophysical goals of Trek, the principle of operation of the detector, and the current status.