Energy dependence of yields of cumulative protons and neutrons in π- A interactions

The proton and neutron yields from the nuclei Be, C, Al, and Pb bombarded by 1.2-5.0-GeV/c π- mesons are measured at the angle of 90 deg. Measurements were conducted by a nonmagnet hadron spectrometer within 60 to 200 MeV energy range of secondary particles. Some properties characterizing approaching the limit fragmentation of nuclei are presented and discussed. The new data prove and specify the conclusion that the lighter is the A nucleus the earlier the yield of cumulative protons becomes independent of the initial pulse. Neutron yield from Be decreases with the growth of the initial pulse, from Al is not changed within the range of errors (3-5%), from Pb increases. Decrease of ratios of yields of neutrons and protons with the growth of the initial pulse within 1.2 to 5.0 GeV/c range is observed for π-Be-, π-Al- and π-Pb- interactions as well as for π-C