Performance characteristics of position-sensitive photomultiplier tubes combined through common X and Y resistive charge dividers

Combining signal channels from detector arrays can improve event throughput and minimize cost but, potentially, at the expense of other performance parameters. In this work, the authors evaluated a method to reduce signal number by combining the anode outputs of up to three position-sensitive photomultiplier tubes (PSPMTs) through a common X and a common Y resistive charge divider. Field flood images of these combined modules were compared to those obtained with independent detectors illuminated individually. No significant reduction in position detection accuracy was observed at low count rates when up to three tubes were combined. Event mis-positioning was also minimal for total count rates <100,000 cps. At higher rates, pulse pileup degraded accuracy. These results suggest that this method of combining PSPMTs may be useful in reducing signal number while maintaining good event localization at reasonable count rates.