Cross sections for the production of 11C in C targets by 12C at relativistic energies

Cross sections for the production of 11C in C targets were measured using 12C ions with energies of 0.40, 1.05, and 2.1 GeV/nucleon. These measurements were undertaken for the purpose of establishing primary standards for use as beam monitors. Annihilation radiation from 11C(T/sub 1/2/ = 20.34 min) was counted using a large volume NaI detector. Cross sections of 63.5 +- 0.5, 57.4 +- 0.4, and 60.9 +- 0.6 mb, respectively, were obtained for 0.40, 1.05, and 2.1 GeV/nucleon 12C beams. The results are compared with earlier measurements of the cross sections in C targets using relativistic proton and α beams. Good agreement is found between the cross sections measured in this work and a simple Glauber theory