Update 08.15.2018 -- Run 9 pp: purity as a function of zTtrk (in bins of eTtrg)

Previously, I reported on the Run9 gamma-rich purity as a function of both zTtrk and eTtrg:

https://drupal.star.bnl.gov/STAR/blog/dmawxc/update-08052018-run-9-pp-purity-function-ettrg-and-zttrk

So to make it easier to parse, below I present the purity as a function of zTtrk in each bin of eTtrg.

And all together now: