According to one embodiment, a circuit comprises a Capacitive Trans-Impedance Amplifier (CTIA) configured to receive a current pulse at an input and convert the current pulse to a voltage step. The voltage step is directed to a first signal path and a second signal path. When the voltage step exceeds a first threshold, the first signal path directs an enable pulse to the second signal path. The second signal path generates an output pulse when the voltage step exceeds a second threshold and the enable pulse is enabled. The second signal path comprises a first, a second, and a third amplifier to increase detection of the voltage step by the second signal path.