Based on an experimentally verified model, the effects of various parameters on the short-circuit current of the beta-voltaic cell are demonstrated. The parametric variables used include electron minority-carrier lifetime and resistivity in the substrate, substrate thickness, surface recombination velocity, Curie content and junction depth. Computed results indicate that with a nominal source curie content of 2·8 Ci/cm 2, a short-circuit current of 80 μA/cm 2 can be achieved when the substrate resistivity is greater than 0·5 Ωcm, substrate thickness greater than 180 μm and an electron lifetime greater than 10 μsec. An increase of current to 90 μA/cm 2 is possible when the back contact is also irradiated by a similar source; under this condition the optimum substrate thickness is 125 μm. A reduction of the surface recombination velocity at the back contact to 10 4 cm/sec increases the optimum current to 114 μA/cm 2 with a substrate of 75 μm in thickness.