A sample of B-10 isotope doped diamond was neutron irradiated to a thermal fluence of 1.3 x 10(19) neutron cm(-2). The diamond sample was cooled continuously during irradiation in a nuclear reactor. Li-7 is formed by nuclear transmutation reaction from B-10. Characterization for electrical conductance in the temperature range of 160 K < T < 600 K was performed on an unirradiated B-10 doped sample and the B-10 doped and irradiated sample. The unirradiated diamond sample showed p-type conductance at higher temperature (T > 200 K) and p-type surface conductance at lower temperature (T < 200 K). The irradiated sample showed decreasing conductance below 230 K and increasing conductance above 230 K with increasing temperature. Furthermore, the conductance showed a decrease above 400 K followed by an increase above 500 K. The observed behavior below 400 K with increase in temperature is interpreted in terms of compensation of surface p-type carriers by n-type bulk carriers generated from Li-7 that is formed by nuclear transmutation reaction from B-10 atoms. Also, compensation of n-type carriers from Li-7 by p-type carriers from 1013 is used to interpret the conductance above 400 K. A low concentration of radiation induced defects, absence of defect complexes, and the low activation energy of n-type Li-7 are thought responsible for the observed variation of conductance in the irradiated diamond. The present results illustrate that neutron transmutation from B-10 doped diamond is a useful method to achieve n-type conductivity in diamond. (C) 2004 American Vacuum Society.