Cross section for the 12C(139La,X)11C reaction at relativistic energies.

The cross section for the /sup 12/C(/sup 139/La,X)/sup 11/C reaction was measured using 1.26-GeV/nucleon /sup 139/La ions. Annihilation radiation from the decay of /sup 11/C was counted using a large volume NaI(Tl) detector. The resulting cross section for /sup 139/La was 147.9 +- 2.0 mb. The results are compared with similar measurements using relativistic /sup 4/He, /sup 12/C, /sup 20/Ne, and /sup 56/Fe projectiles and the predictions of a linear transport model.