The Secondary and Tertiary Particles Produced by Cosmic Rays

Cosmic-ray secondaries and tertiaries have been studied in a series of experiments. It has been shown that the secondaries from lead have little power to produce detectable tertiaries or showers from lead or aluminum. The secondaries from aluminum have been found to produce more showers in lead than the secondaries from air. The absorption coefficient of the secondaries from aluminum has been found to be 0.7 ${\mathrm{cm}}^{-1\mathrm{}}$ Pb and the absorption coefficient of their lead tertiaries 2.0 ${\mathrm{cm}}^{-1\mathrm{}}$ Pb. The values for secondaries from air and a heavy roof, and their lead tertiaries were previously found to be 0.5 ${\mathrm{cm}}^{-1\mathrm{}}$ Pb and 2.58 ${\mathrm{cm}}^{-1\mathrm{}}$ Pb. The values obtained from Rossi's and Funfer's data are 0.32 ${\mathrm{cm}}^{-1\mathrm{}}$ Pb for the air secondaries and 1.18 ${\mathrm{cm}}^{-1\mathrm{}}$ Pb for their lead tertiaries. It follows that the air secondaries and their lead tertiaries have greater energies than the aluminum secondaries and their lead tertiaries. It has been found that a component of the cosmic rays even softer than the corpuscular component is probably the chief source of the secondaries producing the showers. There is some evidence that non-ionizing particles produce a portion of the showers and that possibly non-ionizing secondaries are produced in lead and that these particles can produce ionizing particles in aluminum.