[PRad] target center

[Chao Peng]

Thank you.
It is great to know the target is actually at (0, 0, 88.9) in the current
reference frame we are using. So this explains all the discrepancies we
observed.

Best Regards,
Chao

On Thu, Feb 16, 2017 at 11:24 AM, <gasparan at jlab.org> wrote:

>
>   Thanks Maxime, a good ending.
>  Then, we may fix this as the 12C position and from the Moller events
>  fix the GEM and the HyCal positions (which will include the shower
>  debt correction).
>
>  Ashot
>
>
> > Dear colleagues,
> >
> > Kelly Tremblay checked the survey values for the target since we saw some
> > discrepancies when looking at physics events.
> > Here is his answer:
> > "I checked the fiducialized data from 2015/2016 and verified that the
> > survey team used the center of the chamber for the reference 0,0,0 point
> > for the prad target. This places the coordinates shown in memo B1718
> being
> > 88.9 mm downstream from the referenced Z location. I am not going to
> > change the memo or are target data, but have put flags in the data to
> show
> > the target cell is downstream 88.9 for future reference. The true Z found
> > coordinate position of the target is -385.73294.
> > Hope this clears this up.
> > Kelly"
> >
> > This new value should clear out the discrepancy that we found in the
> > study.
> >
> > Maxime
> > _______________________________________________
> > PRad mailing list
> > PRad at jlab.org
> > https://mailman.jlab.org/mailman/listinfo/prad
> >
>
>
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>



-- 
Chao Peng
Department of Physics
BOX 90305
Duke University
Durham, NC 27708
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