The neutral pion production was studied in subthreshold 60A MeV Ar+C, Ni, Ag, Au reactions. A kinematical fit procedure was applied for a reliable reconstruction of neutral pion kinematics. The transverse momentum spectra are very similar for all studied systems and they are reasonably described by Boltzmann distributions. The temperature parameter does not depend on the total energy available in the system. Perpendicular to backward emission of neutral pions is well described by a simple geometrical model of pion reabsorption.

PACS numbers: 25.70.--z