Aspects of the historical development of targetry for heavy ions of 0.05-2000 A center dot MeV at GSI

The progressively improved GSI accelerators provide beams of heavy ions fro m energies of 0.05-2000 A.MeV at high particle intensities now. Therefore, a wide variety of common and new heavy-ion target techniques had to be inst alled and developed during the past 25 years to prepare and characterize se lf-supported or backed heavy-ion-targets of chemical elements and compounds from hydrogen las polyethylene) to uranium. The thickness ranged from 2 x 10(-6) to 20 g/cm(2) for beam spots of about 5 mm in diameter. Homogeneity, surface structure or individual shape had to be adapted to the needs of ea ch experiment. Special setups were required for targets of poisonous materi als, of highly enriched stable isotopes or those of radioactive species in minute amounts. The capability of thin-layer technologies was as well appli ed to prepare and measure stripper foils or various high-vacuum deposits fo r experimental or accelerator purposes. The development of different rotating target wheels and control mechanisms was enforced by the continuous change of target qualities during high-inten sity heavy-ion bombardments of up to 10(13) particles/s at Coulomb energies . The mass production of complete target systems, especially for the experi ments EPOS, ORANGE and SHIP, required conditional improvement of target rel evant parameters. For relativistic energies up to 2000 A.MeV at the FRS, an automated water-cooled assembly with 75 positions has been developed and i nstalled as production target. The brief historical review can touch only aspects of targetry at GSI. A fe w typical examples are included. (C) 1999 Elsevier Science B.V. All rights reserved.