I have an eight FEE64 system now in place on the LYCCA chamber with a PB-5 pulser going into the adapter cards 
test input. The test capacitor is 30pF.

I was going to explore the effect of the thresholds on the pulser peak.

I notice that the spectra look like those taken in RIKEN and not a single peak. In the 1GeV range I would 
interpret this as noise but since this is such a high energy i don't quite understand what is happening in the 
ASIC.

I thought i would share it with you.

PB-5 input to 50R is 10v with no attenuation. Signal height on the inline 'scope is +5.2v

ASICs are set to "default" with 1GeV range and 3uS shaping time.

Let me know if anything useful can be gleaned by more tests on LYCCA.



Q = CV = 30pF * 5V = 150pC => ~ 3.42GeV => ADC channel ~ 27880

The spectra imply a positive test input. The spectra imply an inconsistency between the data
supplied and the peak position.

You display the spectra on a log scale ...  so the majority of events are in the peak ... but
why do some channels so a peak and others a peak plus a small number of higher amplitude/events?

What ASIC settings are you using?

What is the PB-5 frequency? ... PB-5 settings?