Absorption Length and Collision Length of Hard-Shower-Producing Radiation

By combining techniques of coincidence counter circuits and nuclear photographic emulsions, values are obtained for the absorption length in air of 104±6 (p.e.) g/${\mathrm{cm}}^2$, and for the collision length in paraffin of 61±6 (p.e.) g/${\mathrm{cm}}^2$ for hard-shower-producing radiation. The method also provides evidence of a cascade mechanism by which the hard showers are produced.