The Momentum Spectrum and Positive Excess of Cosmic Ray Mesons at Sea-Level

Abstract

A spectrometer for momentum measurements on cosmic ray particles is described. Charged C.R. particles are deflected in the air gap of an electromagnet and the deflection is recorded by an array of G.M. counters. The momentum distribution and positive excess of particles which penetrate 10 cm. of lead is determined over a momentum range 2.4 x 10⁸ eV/c. to 5 X 10¹⁰ eV./c. from measurements on 6056 particles.