GBS Elektronik MCA-527 How to do an optimum setup - Manual (Page 9)

Preamplifier signal of a CsI detector with photodiode readout. Here only the slow (4*-1;12*0;4*1) trigger filter
works.
The (4*-1;12*0;4*1) may have some practical use for detectors with a really slow rise time (e.g. CsI, SrI) as the
other filters are far to insensitive for this slow signals. Further filter optimization for those slow detectors may
still be done.
Trigger filter sensitivity:
Normally the default here
should do.
Typically, the treshold is
adjusted automatically. For
this the RMS noise on the
trigger filter output signal is
calculated, and the threshold
is set to 7 times this value.
This is normally high
enough so that triggering by
noise very seldom occurs.
However, this assumes that
noise is gaussian
distributed.
Especially at high
amplification levels also
periodic noise (e.g. from switch mode power supplies) may show up and this is not correctly suppressed. In this
case it may be necessary to increase the threshold until noise is not visible any more.