[Halld-tracking-hw] Gas puzzle update

[nsj at cmu.edu]

I now have the cosmics data with the prototype using JLab (production)
preamp & hvb.  Thankfully there is no significant difference between that
and the data using CMU (First article/prototype) electronics.

The data set which I showed at the meeting for 55/45 had been analyzed
using the window times for the JLab data, ie this one set was complete
garbage.

The progression in MPV amplitude & max drift time with Argon is

50% Ar  max-amp MPV 204, max drift time 673ns
55% Ar  max-amp MPV 425, max drift time 609ns
60% Ar  max-amp MPV 932, max drift time 541ns

For the CDC at JLab run 2016 cosmics I found

        max-amp MPV 621, max drift time 572ns


The wire used for the CDC is slightly larger diameter than the prototype
(20um, 18um) and the straw radius is slightly smaller (0.77cm, 0.79cm).

The histograms are here: 
https://halldweb1.jlab.org/wiki/index.php/CDC_prototype_runs_at_CMU


Naomi.