[G8b_run] Follow up to meeting

[Brian Vernarsky]

Hello all,

I spent some time this afternoon making a few of the plots that were
requested at the meeting this morning.  I have just added them to the
pdf from this morning.  You can find it at:
http://www.andrew.cmu.edu/user/bvernars/2013-03-26_g8b_Meeting.pdf

What I added were the TOF TDCs and ADCs for events with one good TDC
and one bad TDC (i.e. one below 4096 and one above), as well as ones
where both TDCs are below 4096.  The first one shows how likely it is
that we can recover an event if one of the TDCs is bad but the other
one is ok, and the second one shows that some of the events will
likely be unsalvagable.  The one caveat to these plots is that all
events from paddles that given a bad status flag will show up as bad
(red); the entirely "bad" paddles generally had about half of their
TDC values above 4096, but half below; unfortunately there was no way
to account for this.  Please note that I've used the same scale for
all the TDC plots so you can easily compare how big the contributions
are.

I also tacked on a slide at the very end that shows the phi
distribution for single proton and single pi+ events to see the effect
of the start counter inefficiencies.  These plots are made with events
from a single amorphous run, 48133, and include both "good" and "bad"
TOF paddles; in short, this is a separate issue from the TOF problem
and I'm not compounding things by removing bad TOF paddles and showing
the start counter inefficiency.  The proton is largely unaffected, but
sector 3 shows a definite bump in the middle of the sector.  However,
the pi+ in all sectors shows a marked inefficiency.  Interestingly it
always seems to be more inefficient on the first two paddles of a
sector.  Also notice the soft shoulder on the left hand side of each
sector, compared to the harder fall off on the right hand side; note
sectors 3, 5 and 6 as good examples of this.

I also added which runs were used in the making of each plot to the slides.

Lastly, Michael and some others were interested in the possible gain
in statistics in the single particle topologies.  I did just a quick
counting exercise on a few runs and it looks like a maximum of 2% of
the single proton events have TOF = 0 and 19% of the single pion
events have TOF = 0.  This would lead to an increase in statistics of
almost 25% for the pions if we could recover every event, which we
can't, but still should yield around a 20% increase.  One caveat on
those numbers, it is possible that some of the missing protons are in
fact being labelled pi+s because with no timing info the positive
tracks with a huge beta are assigned as pions.  I don't think that it
is a huge issue (mainly because the "good" events don't seem to have a
dip that is unaccounted for), but it could mean there are "some" more
protons that are being missed, however I don't expect the increase in
statistics for the single proton events to be much more than 2-3%.

Were there any other questions this morning that I have not answered?

Brian