Energy Determination of Heavy Primaries in Nuclear Emulsion

The "knock-on electron" method has been used to determine the energy per nucleon of the heavy primary particle. In this method, the energy of the primary particle is determined by measuring the emission angle and the energy of the knock-on electrons. The conditions for the reliable estimate of the primary energy by this method are discussed. This method is applied to 34 flat events, of primary energy between 3 and 30 Bev/nucleon and of charge $Z>\mathrm{}4\mathrm{}$, which make nuclear interactions and break up into 2 or more $\alpha$ particles. The energy of the primary particle obtained by knock-on electron method is then compared with the energy obtained by (i) opening angle of $\alpha$ particles and by (ii) relative scattering measurements of $\alpha$ particles. The results obtained by knock-on electron method are quite consistent, within the experimental error, with the results obtained by other methods.