adc spectra for BCAL test run 2334

[Alex Dzierba <dzierba@indiana.edu>]

Dear All

  Please see the attached which shows some peculiarities in ADC
spectra for run 2334 (z=0, normal incidence).  I see similar
peculiarities in the cosmic ray data runs which led me to look
at our 'golden' run,

The first plot shows the ADC spectra for north and south PMT's.
There is one entry per PMT.  My understanding is that the ADC
value in the data file has been pedestal subtracted.  Note two
things:  negative values and the shapes of the North and South
spectra are different for small values of ADC.  For this run
the photon beam is incident at 90 degrees and in the center.

To compute calorimeter energy we sum ADC's

The next plot show a distribution for the ratio of North to
South ADC values - one entry per each of 18 modules.  Note
the quantization.  The corresponding average value of beam
energy for each bin in the ratio is shown.

The next plot is similar - but now the average of North (South)
ADC is shown for each bin in the ratio.

Also note that when compare energy deposition per layer with
simulations - there is a breakdown below beam energies of 300 MeV.

Cheers
Alex
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alex R. Dzierba
Chancellor's Professor of Physics (Emeritus)
Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
JLab Visiting Fellow
Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
Home Phone: 812-825-4063  Cell:  812-327-1881  Fax: 866-541-1263
http://dustbunny.physics.indiana.edu/~dzierba/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

adcs_2334.pdf