Question regarding Pulse shape's effect on the finite slope of GM-tube

[abotiz]

Hi,

I am hoping someone here could help me understand the finite slope of the counting plateau in Geiger Muller Tubes.

Master Knoll says this,

"In real cases, the counting plateau always shows some finite slope, as shown in Fig. 7.5b.
Any effect that adds a low-amplitude tail to the differential pulse height distribution can
be a contributing cause of the slope. For example, some regions near the ends of the tube
may have a lower than normal electric field strength and the discharges originating in these
regions may be smaller than normal. Also, any pulses that occur during the recovery time
will also be abnormally small."


He also says this,

"Another cause of slope in the plateau of many G-M tubes is the occasional failure of
the quenching mechanism which may lead to a satellite or spurious pulse in addition to the
primary Geiger discharge"

Which I understand, because the slope in the counting curve is nothing else than - additional pulses.

But the first thing he writes makes no sense to me. Why would the counting system register additional pulses if the signal amplitude is "deformed" this should only affect the value of the total integration of the pulse, not the amount right?

Thank you very much!

 

[anorlunda]

But the first thing he writes makes no sense to me. Why would the counting system register additional pulses if the signal amplitude is "deformed" this should only affect the value of the total integration of the pulse, not the amount right?

Pulse counting is not just a simple matter of integration. There must be a pulse detector circuit, and obviously it must be sensitive to the actual shape of the pulses.