Low-noise charge-sensitive preamplifier and method for reducing input capacitance

Abstract

The invention relates to the nuclear instrument electronic technology, in particular to a low-noise charge sensitive pre-amplifier and a method for reducing input capacitance. The amplifier comprises a charge collecting electrode, a shielding layer, a Guardring, an amplifier and a clamping diode D; and the charge collecting electrode, the shielding layer and the clamping diode D are all connected with the amplifier. The amplifier can effectively reduce the ground capacitance of the detector and the parasitic capacitance of the input wire and the input MOS tube through the shielding technology, so that the input capacitance of the charge sensitive preamplifier is reduced, the final input total capacitance is the self-ground capacitance of the detector, the input capacitance of the charge sensitive preamplifier can be effectively reduced, and the ENC performance is further improved.

Description

technical field [0001] The invention belongs to the technical field of nuclear instrument electronics, in particular to a low-noise charge-sensitive preamplifier and a method for reducing input capacitance. Background technique [0002] The preamplifier is widely used in the detection and processing of the weak signal output by the detector in the field of nuclear physics to improve the signal-to-noise ratio of the entire system and reduce the signal output by the detector from external interference. At present, the preamplifiers used for this weak signal detection and processing include three types: voltage sensitive, current sensitive and charge sensitive. Among them, the charge sensitive preamplifier is widely used because of its stable gain and high The ratio is a key specification for charge-sensitive preamplifiers, and the signal-to-noise ratio increases with increasing detector input capacitance. [0003] Traditional charge-sensitive preamplifiers such as figure 1 A...

AI Technical Summary

Problems solved by technology

However, the input capacitance of the detector is closely related to the size of its charge collection electrode, and is affected by the parasitic capacitance of the wiring and the input MOS transistor, and the feedback capacitance Cf is too small, which will lead to poor consistency

[0007] The input capacitance of the traditional charge-sensitive preamplifier is the sum of the capacitance of the detector to ground, the input wiring and the parasitic capacitance of the input MOS tube, which cannot reduce or eliminate these three capacitances, and the traditional charge-sensitive preamplifier needs to To improve ENC performance, Cf needs to be reduced, but it will increase the difference in Cf between different pixels or between different chips, which will eventually lead to inconsistent charge conversion gains between different pixels or between different chips

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