Open Access

Kevin L. Wolf, Hans Herbert Gutbrod, W. G. Meyer, Arthur M. Poskanzer, Andres Sandoval, Reinhard Stock, Jean Gosset, Jean Claude Jourdain, Chuck King, George King, Nguyen Van Sen, Gary D. Westfall

• Spectra of positive pions with energies of 15-95 MeV were measured for high energy proton, 4He, 20Ne, and 40Ar bombardments of targets of 27Al, 40Ca, 107,109Ag, 197Au, and 238U. A Si-Ge telescope was used to identify charged pions by dE / dx-E and, in addition, stopped pi + were tagged by the subsequent muon decay. In all, results for 14 target-projectile combinations are presented to study the dependence of pion emission patterns on the bombarding energy (from E / A=0.25 to 2.1 GeV) and on the target and the projectile masses. In addition, associated charged-particle multiplicities were measured in an 80-paddle array of plastic scintillators, and used to make impact parameter selections on the pion-inclusive data. NUCLEAR REACTIONS U(20Ne, pi +), E / A=250 MeV; U(40Ar, pi +), Ca(40Ar, pi +), U(20Ne, pi +), Au(20Ne, pi +), Ag(20Ne, pi +), Al(20Ne, pi +), U(4He, pi +), Al(4He, pi +). E / A=400 MeV; Ca(40Ar, pi +), U(20Ne, pi +), U(4He, pi +), U(p, pi +), E / A=1.05), GeV; U(20Ne, pi +), E / A=2.1 GeV; measured sigma (E, theta ), inclusive and selected on associated charged-particle multiplicity.