@Lazar-Demin Thanks very much. Unfortunately, that does not state any absolute photon intensity, but the spectrum is very useful. The intended use is in an experiment where we want to measure bioluminescence emission via the PMT, but at the same time monitor for movement via a camera system. As "normal cameras don't usually need more light than our signal and would introduce too high levels of noise, we are looking for a way to sidestep this issue, and your camera might be a possibility.