Photomultiplier tube is a vacuum electronic device that converts weak light signals into electrical signals. Its advantages and disadvantages are as follows:



advantage:

High sensitivity: The photomultiplier tube combines features such as high gain, low noise, high frequency response, and large signal reception area, and can operate in the spectral region of ultraviolet, visible, and near-infrared regions, with extremely high sensitivity.

Quick response: Due to the use of secondary electron emission to multiply the emitted photoelectrons, photomultiplier tubes can respond to changes in light signals in an extremely short time.

Wide linear range: The output current of a photomultiplier tube is directly proportional to the number of incident photons, and this linear relationship helps to accurately measure optical signals over a wide range.
Stable performance: The photomultiplier tube has stable performance under normal working conditions and can work continuously for a long time.


Widely used: Photomultiplier tubes are widely used in fields such as metallurgy, electronics, machinery, chemical engineering, geology, medicine, nuclear industry, astronomy, and space research.

Disadvantages:

Sensitivity may decrease: When the photomultiplier tube is exposed to strong light or prolonged exposure, its sensitivity may decrease, known as the "fatigue" phenomenon. After stopping irradiation, sensitivity may partially recover.

High dark count: The signals generated by photomultiplier tubes during operation may not all come from photons, but may also come from other particles such as electrons and ions, which are called dark count. The use of hidden numbers can reduce the accuracy and reliability of measurements.

Gain instability: The electron multiplier in a photomultiplier tube consists of multiple electrodes, each of which contributes differently to the amplification of electrons, resulting in unstable gain for a single photomultiplier tube.

Sensitivity is affected by wavelength: photons of different wavelengths have different transmission efficiency in photomultiplier tubes, and when the light deviates from the central axis, it reduces the probability of photons reaching the photomultiplier tube, thereby affecting the sensitivity of the detector.

Poor high voltage stability: The photomultiplier tube requires high voltage during operation, and the stability of high voltage has a significant impact on the operation of the photomultiplier tube. High voltage changes can cause changes in the electronic multiplier structure of the photomultiplier tube, thereby affecting performance such as gain and noise.



Poor seismic resistance: Photomultiplier tubes usually use a glass casing, so their seismic performance is poor.

Expensive and bulky: As a high-precision instrument, photomultiplier tubes are relatively expensive and have a large volume due to their complex structure.

In summary, photomultiplier tubes have many advantages, but there are also some drawbacks. In practical applications, it is necessary to choose appropriate models and parameters based on specific needs and environmental conditions.