A technique has been used to measure electron beams in excess of 200 kA/cm2with energies of 105−106eV. The technique uses a high‐level nanosecond risetime Faraday cup combined with a dielectric differential range filter to separate the primary electrons from low‐energy charge carriers in the transport system. This technique has been the one used to measure primary beam currents in excess of 5×105A with pulsewidths on the order of 100 nsec. When combined with a knowledge of particle energy, power flux and deposition profiles may be inferred. A derivation of the electric field generated at the cup collector is included.