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style="font-family: -moz-fixed; font-size: 13px;" lang="x-western">SHMS
Colleagues,
<br>
<br>
If you are imagining an experiment in Hall-C that will use a detector
system
<br>
other than the HMS or SHMS, you should be aware that the floor space
with
<br>
an unobstructed view of the experimental target will be more limited
than it
<br>
has been in the pre-12GeV era. See the figures posted <a
href="https://hallcweb.jlab.org/doc-private/ShowDocument?docid=691">HERE</a>.
(Username
12gev,<br>
Password makeshms )<br>
<br>
File #1 shows, in two shades of green, the "large" scattering angles
which are not
<br>
shadowed by components of the SHMS when it is 'parked' at its most
forward angle.
<br>
Thanks go to Charles Perdrisat, whose suggestion led to a redesign of
the SHMS
<br>
structure in order to extend this region down to as low as about 50
degrees.
<br>
(Previously, the minimum scattering angle was about 90 degrees.) The
largest
<br>
possible scattering angle has not been determined.
<br>
<br>
File #2 shows the range of "low" scattering angles between the
spectrometers:
<br>
from about 5 degrees to about 30 degrees. Note, however, that placing
a large
<br>
apparatus between the two spectrometers could be difficult or
impossible
<br>
because of the heights of the HMS and SHMS.
<br>
<br>
The angles mentioned above should not be taken as specifications, or
even
<br>
promises. This is a work in progress and we will do the best we can.
The designs
<br>
will be frozen very soon, however. If you are planning an experiment
which
<br>
will be impacted by this, you should discuss it with me promptly.
<br>
<br>
Best regards,
<br>
Howard Fenker
<br>
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