A new time-of-arrival (TOA) control system has been developed at the Argonne Tandem Linear Accelerator System (ATLAS) for very low intensity radioactive ion beams. This new system utilizes a plastic scintillator which intercepts a small fraction of the beam edge particles and measures the time-of-arrival of a bunched beam at the entrance to the ATLAS superconducting linac after acceleration through the ATLAS 9MV tandem injector A radioactive56Nibeam has been accelerated through a 9MV tandem and then injected into a superconducting linear accelerator for further acceleration. The detector has been successful at stabilizing the pre-tandem bunching system with beam currents as low as2×104particles per second. This paper will describe the electronic circuitry developed for this system and details about the control range and limits. ©1999 American Institute of Physics.