Programming 'totalizer' function in oscilloscopes

[khupys]

Hello?

I have this question for some time about the oscilloscope in general.

Recent o'scopes have a function called 'totalizer' As soon as this function is enabled, it starts counting pulses.
But as I attempt to using it as general purpose 'counter/timer' it does not seem to allow setting the 'counting time'.
I'd like to set the counting time(also called dwell time, gating time, etc.) and count only the pulses that came in during the set counting time.

I am doing photon counting from an photomultiplier tube, which currently requires series of electronics chain including fast amplifier+pulse shaper+programmable pulse counter, all of which are already in an ordinary o'scope's hardware. If the o'scope allows to set the counting time and return the total counts via serial bus to the PC running LabView, I can get rid of these electronics chain and connect directly to the PMT output to the o'scope. It seems this can be achieved by rather simple firmware modification in manufacture's part.

Any thought?