Thin Faraday collectors are being considered as a diagnostic of lost alpha particles on International Thermonuclear Experimental Reactor (ITER). In an effort to evaluate the viability of this diagnostic, we are undertaking a series of calculations of the signal levels (A/cm2) for such devices. Preliminary results assuming a model high yield ITER plasma have been obtained for locations near the outer wall assuming a toroidally symmetric vacuum vessel. We find signal levels to be a strong function of foil location and orientation. Specifically the signal level will be optimized at a vertical location 0.5 m above the machine midplane and with the normal to the foil directed in the lower, radially outward, toroidally counterclockwise octant. A foil thus oriented at a radial distance of 15 cm from the vessel wall at a height of 0.583 m above the machine midplane will have an efficiency of 3.5×10−8/cm2 for alpha particles which undergo classic loss during the first ten revolutions around the torus during this model plasma. For the assumed D–T fusion power of this model plasma of 410 MW, this calculated efficiency will correspond to a measured current in the Faraday foil of 1.7 μA/cm2. Future, more realistic calculations must incorporate the effects of an asymmetrical vessel and of toroidal field ripple.