Scintillator identification and performance characteristics of LSO and GSOPSPMT detector modules combined through common X and Y resistive dividers

Combining signal channels from detector arrays can reduce complexity and mi nimize cost but, potentially, at the expense of other performance parameter s. We evaluated a method that reduces the number of signals by combining th e anode outputs of three position-sensitive photomultiplier tubes (PSPMTs) through a common Ii resistive charge divider and three individual Y resisti ve charge dividers. Field flood images at 511 keV of two LSO modules combin ed with a single GSO module were compared to images obtained when the modul es were illuminated separately. At moderate count rates only a small reduct ion in position detection accuracy was observed in the combined tubes. Even t mis-positioning was minimal for total count rates < 300,000 cps. At highe r rates, pulse pileup degraded accuracy. Delayed charge integration, a meth od for identifying scintillators by differences in their light decay times, allowed the LSO and GSO arrays to be distinguished from one another and al so reduced the effect of pulse pileup. Thus, combining PSPMTs anodes throug h common X and common Y resistive dividers may be useful in reducing signal number from PSPMT detector modules while maintaining good event localizati on and scintillator identification accuracy at reasonable event rates.