Formation ofBe7in Interactions of Various Nuclei with High-Energy Protons

Abstract

Cross sections are reported for the formation of Be/sup 7/ in interactions of C, Al, Cu, Ag, and Au with protons of energies between 1 and 3 Bev. They are compared with previous data at 0.34-Bev proton energy. The carbon cross section is strikingly constant at 11 to 14 mb from 0.1 to 3.0 Bev. The other cross sections rise with increasing proton energy and are all in the neighborhood of 10 mb at 3 Bev. Beryllium-7 may be considered as a spallation residue from carbon, and the same mechanism probably accounts for at least a large part of its formation from Al. However, Monte Carlo calculations show that this mechanism predicts much too low cross sections from the higher Z targets. Other mechanisms must be invoked, the most promising being the evaporation of Be/ sup 7/ nuclei. (auth)