Nuclear interactions at 20 to 150 GeV in carbon

Abstract

Nuclear interactions produced in carbon by cosmic ray particles of energy 20 GeV to 150 GeV have been studied using a multiplate cloud chamber at an altitude of 2210 m. At this altitude the ratio of neutral to charged nuclear-active particles iin the above energy region is found to be 0.69±0.13. The average charged multiplicity <n_s for events with n_s 3 is observed to be 5.6±0.2. It is found only (23±4)% of the energy available in the c.m. system is used up for production of π-mesons. The energy spectrum in the laboratory system of the observed γ-rays which result from π⁰-decayturns out to be slightly steeper than that predicted by Heisenberg theory. The momentum spectrum of pions in the c.m. system is given by a varying power law. The average energy of a π meson in the c.m. system is 430±50 MeV. The angular distribution of the created particles in the c.m. system is isotropic. The average value of the transverse momentum of π mesons is found to be 390±25 MeV/c. The ratio of neutral π mesons to charged shower particles amongst the created particles is 0.4±0.04 which, being the same as determined for interactions at energies ≈1000 GeV, indicates that among the created particles the fraction of charged particles which are not pions does not change significantly from 20 GeV to 1000 GeV. The interaction mean free path in brass for the charged secondary particles is determined to be 133±14 g/cm². The ratio of secondary interactions induced by neutral to those induced by charged created particles in the brass plates of the chamber is equal to 0.16±0.07.