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[videbaek <videbaek AT bnl.gov>]

xu said he changed timing from uic/teststand setup to ist settings.
it is my understanding the trigger timing is the same as earlier years 
after several iterations.





On 2021-11-21 16:57, Tonko Ljubicic wrote:
> Hi Gerard,
>
> there was an email about a dramatic change of delays from Xu so
> my guess is that the old value was completely wrong. But Xu should 
> comment.
>
> No clue about GMT. Never bothered to look at that detector :-).
>
>
>
>
> On Sun, Nov 21, 2021 at 10:47 PM Visser, Gerard <gvisser AT indiana.edu> 
> wrote:
> > 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
> >
> >
> > ________________________________
> > 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
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--
Flemming Videbaek
senior scientist
videbaek @ bnl.gov
Brookhaven National Lab
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