ADC distributions for ACD
triggered data
Larry Wai
Oct. 7, 2005
Run info
• All the plots are for the I&T ACD Triggered
Op run 134001103, first 100k events
• Coincidence regions are top-side (x4),
opposite sides (x2), adjacent sides (x2)
Tile ADC asymmetries
• One entry per tile
• 2-D histograms of
adc0 vs adc1
• Range selection on
tile ADCs: (0,0), (1,1),
(0,1), (1,0)
Tiles with large asymmetries
One entry per tile
•
Top left: Histograms of the tile ID number.
Grey is all tiles hit, excluding the NA tiles.
Red shows tiles with (range0,range1)=(0,0)
and (adc0<600, adc1>2000).
•
Top right: Yellow box shows that range
selection is (range0,range1)=(0,0) for the
upper left red histogram.
•
Bottom left: Partially obscured yellow box
shows that the selection for the upper left
red histogram is (adc0<600, adc1>2000).
•
Bottom right: Grey is all tiles hit, excluding
the NA tiles. Red shows tiles with
(range0,range1)=(0,0) and (adc0>2000,
adc1<600).

The tile IDs w/ large differences between
adcs AND (range0,range1)=(0,0) are mostly
in the 500s and 600s.
Regular tile adc asymmetry
• Tile=230
Ribbon adc asymmetry
• “Tile”=600
• This is a ribbon
 Large asymmetry is
expected due to long
length of ribbon
Events w/ large numbers of single
adc hit tiles
One entry per event
•
Top left: number of tiles w/ both adcs above
threshold versus total number of tiles
•
Top right: number of tiles w/ only one adc above
threshold
•
Bottom left: black is distribution of RoiVector
coincidences (8 bit word, lowest bit is coincidence
of lowest RoiVector pair, highest bit is coincidence
of highest RoiVector pair, etc.), red is fraction of
events with more than half the tiles with only one
adc above threshold
•
Bottom right: fraction of events with both adcs
above threshold (the yellow shows the event
selection for the bottom left red histogram)

there's a class of events which don't have as many
tiles with only one adc, and another class of events
which do have a lot of tiles with only one adc. This
class of events doesn't depend upon the regioncoincidence which triggered the event.
More things to check
• Is the number of single adc ACD tiles the
same from runs prior to delivery to SLAC?
• Is this what we expect from Monte Carlo?