An apparatus includes a photodetector configured to generate an electrical current based on received illumination. The apparatus also includes an integration capacitor configured to integrate the electrical current and generate an integrator voltage. The apparatus further includes an amplifier configured to control a transistor switch coupled in series between the photodetector and the integration capacitor. The apparatus also includes an event detector configured to sense a high-energy event affecting the photodetector. In addition, the apparatus includes a switchable clamp coupled across inputs of the amplifier, where the event detector is configured to close the switchable clamp in response to sensing the high-energy event.