  The K0 meson production by pi- mesons of 1.15 GeV/c momentum on C, Al, Cu, Sn
and Pb nuclear targets was measured with the FOPI spectrometer at the SIS
accelerator of GSI. Inclusive production cross-sections and the momentum
distributions of K0 mesons are compared to scaled elementary production
cross-sections and to predictions of theoretical models describing the
in-medium production of kaons. The data represent a new reference for those
models, which are widely used for interpretation of the strangeness-production
in heavy-ion collisions. The presented results demonstrate the sensitivity of
the kaon production to the reaction amplitudes inside nuclei and point to the
existence of a repulsive KN-potential of 20+-5 MeV at normal nuclear matter
density.
