Dear colleagues,
I've updated bg simulation note. A few sections/plots have
been added (I have modified a little bit the text, no big
changes):
  - design of primary collimator
  - thickness of lead wall
  - impact of background on the GlueX detector
A new version is linked to the pre-brief materials for the
review (GlueX-doc-1084-v2) at the tagger review page.
Cheers,
        Alex