Electronics > Projects, Designs, and Technical Stuff
Pole-zero cancellation and preamplifiers
<< < (3/3)
jmelson:

--- Quote from: ChristofferB on May 08, 2020, 10:23:53 pm ---That's the strange thing. The p/z adjustment does nothing to the undershoot. And this is the case on 3 spectroscopy amplifiers.

--- End quote ---
Well, the shaping time is selectable by a switch, does that do anything?  You don't indicate the time scale in your first drawing, so i don't know if your
scintillator tail shape is compatible with the 572 shaping amp.  It might be too fast or too slow, and beyond the range of the P/Z circuit on the 572.

Jon
dmendesf:
I know nothing about spectroscopy but as long as your signal is AC coupled then the output NEEDs to have a mean of zero (so it goes positive and negative). I'm just justifying the behavior here. No idea about how to fix, but integrating the output seems like a good idea.
ChristofferB:
Sorry to revive an old thread, but I wanted to share with you a PMT preamplifier circuit that almost eliminates the issue completely.

The topology is swapped from a 'parasitic capacitance' charge amp to a standard CSA. Works a charm. The network inbetween the two op amps can be used to tweak pulse shape slightly.

I'm quite pleased, see attached schematic.

Thanks for the input!

Navigation
Message Index
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod