Identification of K+-mesons from subthreshold pA collisions with ANKE at COSY-Jülich

The spectrometer ANKE has been put into operation at the accelerator COSY of the Forschungszentrum Jülich in spring 1998. An initial scientific goal is to study K+-production in pA collisions at subthreshold energies far below the free NN-threshold at Tp=1.58GeV. This requires the identification of K+-mesons in a background of pions and protons, about 106 times more intense. In this paper the sophisticated detection system and the software procedures for kaon identification are described. With the help of TOF, energy-loss and range measurements as well as the track information from wire chambers, it is possible to measure d2σ/dΩdp for deep subthreshold K+ production at beam energies down to Tp=1.0GeV.