Star-fst-l mailing list

[Tonko Ljubicic <tonko AT bnl.gov>]

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