Star-fst-l mailing list

["Visser, Gerard" <gvisser AT indiana.edu>]

It seems like GMT is also seeing two peaks. I'm suspecting we are not triggering with a clean timing, whether that is inherent or something not quite right in the trigger setup today, I don't know.

TOF should show this very clearly if there is a single clean peak or two peaks. But I think this kind of timing plot is not in the TOF Jplots, or I don't understand where it is. But we could ask the TOF group to make a plot to check is the data coming in with one clean cosmic peak or possibly two peaks? (Or are you already sure, Tonko, that is is one peak?)

      Gerard

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From: Star-fst-l <star-fst-l-bounces AT lists.bnl.gov> on behalf of Tonko Ljubicic <tonko AT bnl.gov>
Sent: Saturday, November 20, 2021 12:08 PM
To: Star-fst L <star-fst-l AT lists.bnl.gov>
Subject: [Star-fst-l] FST timing relative to trigger

 

Hello,

what I think we should do is make _sure_ we are
seeing the correct trigger crossing. Looking at the
timebin plots (where the x-axis is the timebin, 0 to 9)
I'm not sure we do. We see 2 peaks which I don't
understand at all.

First, we should make the ZS data used in the plot
more stringent, with a higher N-sigma cut so that
we think it is an actual particle and not just noise.
For this exercise I would even exaggerate a bit,
e.g. 6 sigma.

Secondly, we should do a quick scan of the global
APV latency-from-trigger (there is such a register,
can't remember the actual name) by moving it in
e.g. 100ns steps or so. Where does the current
setting come from, BTW? Gerard?

I picked up a Cosmics run with IST from 2015
and you can find the same plot attached. Note the
peak.

           -- Tonko