A Photomultiplier Tube (PMT) is a highly sensitive device used to detect light. It works by converting incoming photons into an electrical signal. When light hits the tube, it releases electrons, which are then amplified through a series of dynodes, creating a larger current that can be measured. This makes PMTs essential in various applications, such as in scientific research, medical imaging, and nuclear physics. PMTs are particularly useful in low-light conditions, where traditional detectors may struggle. They can detect single photons, making them invaluable in fields like astrophysics and particle physics. Their ability to provide precise measurements helps scientists explore the universe and understand fundamental particles.