[G12] CC time vs SC time question

[Johann Goetz]

The CC timing is so poor in resolution that this hardly matters to anyone.
I believe we have no incentive to align timing in the CC to the event time.
The EC timing is sometimes used as a substitute for a missing TOF hit, but
that's a relatively small effect. Also, what are the units on time? Both 50
ps and 50 ns do not make sense for the TOF (should be 100-200 ns). This
should be normalized to the event time (RF or tagger or even ST would
work).

On Tue, Jul 14, 2015 at 3:09 AM s.schadmand <s.schadmand at fz-juelich.de>
wrote:

> my guess is that these are the absolute times and only the magnitude of
> the difference in ns needs to make sense. who has a smaller absolute time
> entry depends on cable lengths and readout, common start/stop or clocking?
>
>
>
> > On Jul 14, 2015, at 07:25, Michael C. Kunkel <mkunkel at jlab.org> wrote:
> >
> > Greetings,
> >
> > Michaela Schever, Masters student at Forschungszentrum Jülich working
> with g12, has asked me a question that puzzles me.
> >
> > Please look at
> >
> https://clasweb.jlab.org/rungroups/g12/wiki/index.php/CC_Study#Tuesday_July_14.2C_2015
> >
> > Notice the y axis is the cc_time and the x axis is the sc_time.
> > The question was why is the cc time greater than that of the sc time,
> considering the TOF is located after the CC and also why the negative slope?
> >
> > I did look in the code and noticed that these quantities are grabbed
> from the TBID bank, which has both cc and sc time in ns.
> > I also looked into some of the calibrations and did not see anything
> striking that would answer this.
> >
> > Please help us understand this.
> >
> > BR
> > MK
> > ----------------------------------------
> > Michael C. Kunkel, PhD
> > Forschungszentrum Jülich
> > Nuclear Physics Institute and Juelich Center for Hadron Physics
> > Experimental Hadron Structure (IKP-1)
> > www.fz-juelich.de/ikp
> >
> > _______________________________________________
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> > G12 at jlab.org
> > https://mailman.jlab.org/mailman/listinfo/g12
>
>
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