Photomultiplier tubes (photomultipliers or PMTs for short) are extremely sensitive detectors of light in the ultraviolet, visible and near infrared. These detectors multiply the signal produced by incident light by as much as 108, from which single photons can be resolved. The combination of high gain, low noise, high frequency response and large area of collection have meant that these devices still find applications in nuclear and particle physics, astronomy, medical imaging and motion picture… (More on Photomultiplier)