An Evaluation of Some New Phototubes with High Gain First Dynodes

We have examined high gain first dynode phototubes for use in a multicell gas Cherenkov counter at Fermilab. Price and availability dictated a careful examination of the EMI9839KB. Preliminary laboratory tests followed by test beam evaluation indicated that these tubes were adequate. We report here how the best of more than sixty of these tubes were selected based on their quantum efficiency, single electron resolution, gain and noise. Using the same test procedures we then evaluated small samples of Hamamatsu R1332, Amperex PM2262 and RCA 8850 tubes. We also report pulse height resolution and pulse shape data on the Hamamatsu R1262X phototube. We conclude that all four manufacturers now produce tubes with useful single photoelectron resolution and fast time response.