Abstract: By the combination of charged particle activation analysis (CPAA) with channeling, we have measured the 11C radioactivity from the reaction 10B(d,n)11C using irradiation of about 2. 7 MeV deuterons along <100>,<110> and random directions of LEC (Liquid Encapsulated Czochralski) grown GaAs. With our theoretical treatment based on the channeling theory, we have calculated the lattice location of boron in LEC GaAs. Our results show that the boron atoms are principally located at the substitutional position (>95%). These results are consistent with those obtained by other methods.