[d2n-analysis-talk] BB cer peds

[posik at jlab.org]

Hi all,

 I have looked at the ped values from the runs that I showed in our
meeting yesterday

https://hallaweb.jlab.org/wiki/images/0/04/Posik_20100217.pdf

These runs cover a range of currents, as well as run times. I compared
various 1881 ADCs

http://jlab.org/~posik/d2n/BB/cer/peds/ped_values/pedsVcurrent.ps

In the above plot, each color represents a different current. The x-axis
is PMT tube and the y-axis is the ped value which was found by fitting a
gauss to the beam on ped.

 As you can see the ped values overlap fairly nicely. The one exception in
this plot is PMT 9, but I feel this is because the statistics on that
particular tube is not great. You can see my fits for all plotted runs
below:

http://jlab.org/~posik/d2n/BB/cer/peds/ped_values/1849_ped_values_2.ps
http://jlab.org/~posik/d2n/BB/cer/peds/ped_values/1949_ped_values_2.ps
http://jlab.org/~posik/d2n/BB/cer/peds/ped_values/1976_ped_values_2.ps
http://jlab.org/~posik/d2n/BB/cer/peds/ped_values/2149_ped_values_2.ps

Looking at these plots I don't think that our peds will be shifting from
run to run.

I also fitted a run 1314, a 13uA run on the v792 ADC. Those fits can be
seen here:

http://jlab.org/~posik/d2n/BB/cer/peds/ped_values/1314_beam_ped_values_2.png

If this looks ok, I will start to enter these new ped values into the DB
files.

Thanks
Matt