Non-contact object surface charge photomultiplier tube amplifier

Abstract

The invention relates to a non-contact object surface charge photomultiplier tube amplifier, belonging to the technical field of signal detection. The principle is as follows: the intensity of incident light is determined by the number of photons passing through a unit vertical area in unit time, and if the number of photons passing through a metal surface in unit time increases, the number of times that photons collide with the electrons in the metal increases, the number of photons escaping from the metal surface in unit time increases, and the photocurrent increases; and if the intensity of incident light remains unchanged and the number of times that photons collide with the electrons in the metal increases due to increase in the number of charges on the metal surface, the number of photoelectrons escaping from the metal surface in unit time increases. The number of photoelectrons is multiplied constantly by a photomultiplier tube, and the number of electrons collected by the anode finally can be increased 104-108 times. Because of high sensitivity and low noise of the photomultiplier tube, weak charge signals on the surface of a sample can be detected. The non-contact object surface charge photomultiplier tube amplifier can be widely used in the field of charge detection.

Description

technical field [0001] The invention relates to a charge photomultiplier amplifier on the surface of a non-contact object, which belongs to the technical field of signal detection. Background technique [0002] The main function of the charge amplifier is to convert the amount of charge into a corresponding output voltage, which requires extremely high input impedance and a good integral relationship between the output and the input. In fact, the charge amplifier is also an operational amplifier. The difference is that the charge amplifier is different from the ordinary operational amplifier: the input end uses Li-COMS technology, so that the input bias current is extremely small, basically at the fA level. The input stage is relatively weak, because of the input impedance of the charge amplifier, there is no protection circuit such as ESD inside. The bandwidth of the amplifier is very narrow because of the low-voltage and low-leakage characteristics of the low-leakage MOS ...

AI Technical Summary

Problems solved by technology

There is another type of detection, which is to detect the amount of charge on the surface of the object. The greater the charge density on the surface of this type of detection object, the higher the voltage, and the shape of the charge density on the surface of the object cannot be destroyed during detection. This kind of special requirements In the detection process, the sensor and the surface of the object cannot be contacted, so a non-contact sensor is required, and the voltage generated by the charge on the surface of the object is extremely weak, and at the same time it must meet the non-contact requirements. This type of detection At present, there is no effective means. For the detection of electrostatic charge, usually only electrometers can be used. Obviously, electrometers cannot meet the requirements, so this problem needs to be solved.

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