The magnetic spectrometer ANKE has been put into operation in spring 1998 at the cooler synchrotron COSY--Juelich. ANKE allows to momentum analyze ejectiles emitted from an internal target at forward angles \vartheta \approx 0^\circ with high angular acceptance \Delta \Omega  \approx 50 msr. A primary goal of the physics program with ANKE is the investigation of K⁺ production in proton--nucleus collisions at energies around and far below the free nucleon--nucleon threshold at T=1.58 GeV. The measurements have been performed with C, Cu and Au targets at various energies in the range T=1.0, ..., 2.3 GeV. The major experimental challenge is that the kaon-to-background ratio is as low as \sim 10^-6 at the lowest energy. Data on the target--mass dependence of the production cross sections for kaon momenta p_K⁺ = 150, ..., 510 MeV/c  at beam energies of T=1.0 and 2.3 GeV are presented.

PACS numbers: 25.10.+s, 13.75.--n, 13.60.Le