Pion production at small angles

Abstract π + and π − production cross sections for 800-MeV protons on C and Cu have been measured at laboratory angles of 0°, 3°, 5°, 7°, 10°, 15°, and 20°. Pions were analyzed using the High Resolution Proton Spectrometer (HRS) facility for momenta from 364 to 675 MeV/ c . Particle identification was made utilizing a time-of-flight method. We estimate the total systematic and statistical error to be ±15% for measurements at 0° and 3° and ±10% at other angles. These data have been used to determine the optimum energy and pion production angle for injection into a proposed superconducting accelerator for pions. Protons are the main source of contamination for a π + beam. Proton-to-pion ratios are given for laboratory angles of 5° and larger.