Evaluation of LAPPD photosensors in a high-rate environment for gas Cherenkov detectors

The solenoidal large intensity device (SoLID) spectrometer gas Cherenkov counters require photosensors that operate in a high luminosity and high background environment. Multi-anode photomultipliers (MaPMTs) were chosen as the photosensors for the reference design. Recently developed Large Area Picosecond Photodetector (LAPPD^TM) shows great potential as an alternative photosensor to replace MaPMTs in this application. We evaluated the performance of two version LAPPDs, namely the stripline baseline LAPPD and the pixelated LAPPD, under realistic SoLID running conditions in Hall C at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The performance of MaPMT arrays were also tested for comparison. The test beam results show that the MaPMT array and the LAPPDs can detect and identify single-electron and pair-production events in high-rate environments. Due to its higher quantum efficiency, the MaPMT array provided a better separation between the single-electron and the pair-production events compared to the LAPPDs. Although the design was not aimed at Ring Imaging Cherenkovs, Cherenkov disk images were captured by pixelated LAPPD in two different gas radiators. Through a direct comparison with a GEANT4 simulation, we confirmed the experimental performance of the stripline baseline LAPPD and pixelated LAPPD.