| 摘要 |
PURPOSE:To prevent a photomultiplier tube from damaging by stopping power supply to the photomultiplier tube and the closing operation of a shutter when the intensity of external light is great. CONSTITUTION:When the level of external light is greater than a set value, a relay 31 is operated by the output of a photodetector once a power switch 27 is turned on, allowing a hook H to fall. Therefore, part 28a of a rotor 28 is hooked by an operating pin F to stop the rotation of the rotor 28. Then, a driving plate 26 is not pushed up and a shutter 22 is disabled to open. In this state, when a knob is turned off, a blade 28 presses the hook H up, and it stops by being hooked by the driving pin G of the relay. When this relay 31 when operating turns off a power source with a switch J, so the power source is turned off immediately after the hook falls, preventing the unnecessary consumption of electric power. |
