Nuclear Interactions of High-EnergyμMesons in Carbon

A multiplate cloud chamber containing two large plastic scintillators capable of selecting nuclear interactions is described. Forty-three interactions, attributed to energetic $\mu$ mesons, have been observed in the chamber and the following cross sections for interactions in carbon obtained: (5.6±1.1)×${10}^{-30\mathrm{}}$ ${\mathrm{cm}}^2$/nucleon for all interactions involving energy transfers >50 Mev and (1.7±0.6)×${10}^{-30\mathrm{}}$ ${\mathrm{cm}}^2$/nucleon for shower production. It is shown that several aspects of the interactions can be reasonably accounted for with the aid of the semiclassical Williams-Weizsäcker method and the results are used to infer photon interaction cross sections in carbon for photon energies up to about 10 Bev. The $\mu$-meson cross sections reported here are in agreement with those found by George and Evans using emulsion techniques, but some of the details of the interactions differ and it is suggested that an appreciable fraction of the stars observed in an emulsion exposed underground may be due to $\pi$ mesons or protons.