Patent ID: 8891979

Claim:
A photon detection system comprising: a photon detector configured to detect single photons, the photon detector being configured to generate an output signal comprising voltage spikes generated in response to single photons and a periodic component, wherein the voltage spikes are superimposed on the periodic component; a voltage source configured to apply a gating signal to the detector as the periodic component, the gating signal comprising a voltage signal which swings above and below a breakdown voltage of the photon detector; a signal divider to divide the output signal of the photon detector into a first part and a second part, wherein the first part is substantially identical to the second part; a delay line configured to delay the second part with respect to the first part by an amount selected according to the period of the gating signal; a combiner for combining the first and delayed second parts of the signal to obtain a combined signal such that the delayed second part is used to cancel the periodic component in the first part of the output signal; and a discriminator configured to compare the combined signal with a discriminator level and to determine the detection of a photon in response to a peak and/or a dip in the combined signal.