a system and method for suppressing secondary electron counts in systems that count particles . the secondary electrons are produced in a foil or other secondary electron emitting surface . a suppression grid is placed in front of the particle detector . the grid is held at an applied voltage that prevents some portion of the electrons from being transmitted through the grid and reaching the detector . the applied voltage may be adjusted and varied in a manner that provides a predicable electron count and an enhanced dynamic range of measurements at the detector .