[Halld-tagger] Question at the run preparation meeting

[Richard Jones]

Hello Alexandre,

Yes, I would like to recommend that we run in the fall with the quadrupole
turned on. Dan Sober's ray tracing showed that the gradient we want to
obtain the correct focus at 12 GeV endpoint is around -630 G/cm. During our
tests in spring 2016, we determined that the current around -4.3 Amps
achieves the desired gradient, in agreement with the excitation curve that
Todd shared with us and that I posted on our wiki at
http://zeus.phys.uconn.edu/halld/tagger/quadrupole-magnet/QPexcitation_curve-3-31-2016.txt

Based on the expected beam energy reduction from 12 GeV to 11.6 GeV, I
recommend running the quadrupole at 4.2 A in fall 2016.

-Richard Jones

On Thu, Sep 1, 2016 at 8:06 AM, Alexandre Deur <deurpam at jlab.org> wrote:

> Good morning Richard,
>
> One question that came up at the run meeting last week was whether we
> should run with the tagger quad on or off. What is your recommendation?
>
> Thank you,
>
> Alexandre
>
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