US' Single Photon Counter allows you to register and count single photons in 1 sec, 10 sec or external (user defined) time window. The device has standard fiber input, BNC input for external counting window.
The measurement for 1 sec and 10 sec regimes starts by the "Start" button. Or in case of "Extermal window" regime choosen, the photons are counted inside the first full external impulse.
The results for external window regime are stored separately.