Deadtime in Geiger Muller Tubes

[cmug]

Thanks for your answer. Yes that's part of my intrest. I knew the deadtime from datasheet. I measure with the oscilloscope. And next step is to do the two source method. And compare these figures.
I don't think I could do the two source method at home with household stuff. But I can ask university of Utrecht, they come always in the winter at our school with a lot of equiment and experiments with ionizing radiation.
Also read in the latest artikel from eliocor (Dead Time Effects on Gamma Detectors). As I understand it well, dead time is only serieus problem with very high counts per time unit.