Re: TOF constant fraction

[Alexander Ostrovidov <ostrov@hadron.physics.fsu.edu>]

Hall D PID Mail List:

  Benni,

Thanks for your comments. Paul is already looking
if we can get hold of other CFD types for the test. 

Regarding V812: the delay is indeed set at 20ns. Per 
your suggestion, we'll do a measurement at 4ns to see
if this makes any difference. 

Doing ADC "time-walk corrections" to CFD is not
trivial for us at the moment because the simple
trigger logic we use does not allow us to match
a TDC event in a multi-hit F1TDC with an ADC event
in a single-hit CAEN ADC we have at the moment.
Our plan is to wait for the flash ADC to arrive, and
then build a more complex "synchronized" trigger logic
for this specific TDC/ADC pair.

I'm still trying to digest your suggestion to split a signal
into low- and high-threshold discriminator channels and
then combine them again. Does this eliminate all the
small signals between low and high thresholds which
we want to keep? Does an addition of a fan-in/fan-out 
unit introduce its own time-walk?

Sasha