The dark current noise of PMT (photomultiplier tube) refers to the current value and related noise output by PMT in the absence of light incidence.



The following is a detailed explanation of PMT dark current noise:

Definition of dark current:

Dark current is caused by random thermal fluctuations that provide sufficient energy to enhance the passage of electrons through the bandgap, thereby forming electron hole pairs. These electron hole pairs are separated by a local electric field, and free electrons are stored in pixel wells.
At a given temperature, the rate of generation of electron hole pairs is called dark current.

The source of dark current noise:

Scattered noise causes fluctuations in dark current, resulting in dark noise. Dark noise is a form of shot noise that is directly related to dark current.
A longer integration time will result in a higher number of electrons required to form dark currents, so dark noise is also related to the integration time.

The influencing factors of dark current noise:

Temperature: Dark current and dark noise are closely related to device temperature. At high temperatures, both the dark current and dark noise of PMT will increase.
Humidity: Excessive humidity may lead to an increase in leakage current, indirectly affecting dark current noise.
Working voltage: The sensitivity, gain, and dark current of PMT are all related to the working voltage. The selection of working voltage has a significant impact on dark current noise.

Methods to reduce dark current noise:

Thermoelectric cooling: Using TEC cooling can significantly reduce dark current and dark noise.
Choose the appropriate working voltage: Engineers usually recommend a voltage range to achieve a higher signal-to-noise ratio.
Maintain stable environment: Avoid drastic changes in temperature and humidity, and maintain a stable working environment for PMT.

The importance of PMT dark current noise:

Dark current noise is one of the important indicators of PMT performance, which directly affects the signal-to-noise ratio, sensitivity, and other performance of PMT.
In some applications that require high levels of noise, such as spectral analysis and weak light signal detection, reducing the dark current noise of PMT is particularly important.



The dark current noise of PMT is caused by the current and related noise generated by electron hole pairs generated by random thermal waves in the absence of light incidence. Understanding the sources, influencing factors, and reduction methods of dark current noise is of great significance for optimizing the performance and application of PMT.