Two different systems have been built to study the geomagnetic field effect on the performance of large area photomultiplier tubes. The main characteristics of photomultiplier tubes such as gain. collection efficiency. transition time spread and energy resolution were measured to investigate the effect. https://www.jmannino.com/best-catch-Sophie-Allport-Bee-Blackout-Ready-Made-Eyelet-Curtains-Duck-Egg-special-save/