Design and commissioning of the GSI pion beam

We describe the design of the secondary pion beam-line installed at the SIS 18Tm synchrotron at GSI, Darmstadt, and discuss the commissioning results. The experiments were performed with proton and 12C primary beams at several energies using beryllium production targets. Pion yields in a momentum range between 0.4 and 2.8 GeV/c were identified. At the highest primary beam energies of 3.5 GeV for proton and 2.0 A GeV for carbon ions, the latter beam produces the highest low-momentum pion yield while at momenta of 1.5 GeV/c the yields are comparable and at 2.8 GeV/c the proton beam is superior. A momentum resolution of around 0.5% is achieved and the time resolution (σ) ranges from 100 to 150 ps, for bombarding rates up to 1.5 MHz.