ZDependence of Positive Pion Production by 340-Mev Protons

The relative yield of positive pions produced in various elements by the 340-Mev external beam of protons from the 184-in. Berkeley cyclotron was measured using a counter telescope to identify the mesons. The target materials used were Li (normal), Be, ${\mathrm{B}}^{10}$, ${\mathrm{B}}^{11}$, C, Al, Cu, Ag, and Pb. Mesons from these elements with energies 36±4 Mev and 63±4 Mev were observed at an angle of 135° relative to the proton beam.