Combining signal channels from detector arrays can reduce
complexity and minimize cost but, potentially, at the expense
of other performance parameters. We evaluated a method that
reduces the number of signals by combining the anode outputs
of three positiCombining signal channels from detector arrays can reduce
complexity and minimize cost but, potentially, at the expense
of other performance parameters. We evaluated a method that
reduces the number of signals by combining the anode outputs
of three position-sensitive photomultiplier tubes (PSPMTs)
through a common X resistive charge divider and three
individual Y resistive charge dividers. Field flood images at
511 keV of two LSO modules combined with a single GSO
module were compared to images obtained when the modules
were illuminated separately. At moderate count rates only a
small reduction in position detection accuracy was observed in
the combined tubes. Event mis-positioning was minimal for
total count rates < 300,000 cps. At higher rates, pulse pileup
degraded accuracy. Delayed charge integration, a method for
identifying scintillators by differences in their light decay
times, allowed the LSO and GSO arrays to be distinguished
from one another and also reduced the effect of pulse pileup.
Thus, combining PSPMTs anodes through common X and
common Y rcsistivc dividers may be useful in reducing signal
number from PSPMT deteclor modules while maintaining
good event localization and scintillator identification accuracy
at reasonable event rates.[+][-]
