| 摘要 |
An external calibration system for a photo multiplier tube is described. The calibration system uses a light emitting diode and a photo cell wherein the diode is domed shaped. The light sensitive face of the photo multiplier tube is contained in the plane disposed at an acute angle to the longitudinal axis of the light emitting diode, and the photo cell is mounted substantially perpendicular to the longitudinal axis. A source of electrical energy then illuminates the light emitting diode over a range from, for example, 0 to 5 volts to generate light of known intensity and the light being generated is simultaneously measured by the photo cell and the light sensitive face of the photo multiplier tube. A feedback circuit is provided and associated circuitry so that a number of readings can be taken over a wide variety of light intensities to generate a calibration for the photo multiplier tube.
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