A single 50‐Mc cavity electron accelerator has been built. When operating in the TM010mode, it is capable of delivering a 29‐amp, 0.2‐&mgr;sec, 8‐Mev, 2‐cm radius beam to a target downstream from the cavity. When focused to a 3‐mm‐diam spot, the beam current is reduced to about 9 amp; the resulting radiation flux is about 1.2 r at one meter for a 0.2‐&mgr;sec pulse length.