The Research Of Weak Signal Vector Detection Technology Of Signal-to-Noise-Ratio Detection In MCP

Microchannel plate(MCP) is the core component of image intensifier, which can multiply the stream of electrons distributed in two-dimensional space, in which, gain and signal to noise ratio is main parameters evaluating MCP. A kind of weak electron flow test device is needed for characteristic test of MCP due to its extremely weak output current.This paper finds out, through investigation of the development status of MCP and low current detector, that conventional current detector is not suitable for characteristics of signal-to-noise ratio detection system of MCP. Therefore, after analysis of characteristics of MCP and motion trail of output electron, this paper designs a weak electron beam detection system that is most suitable for this specific environment and can apply to MCP signal-to-noise ratio detection system. The specific scheme is as follows:The system is mainly divided into three parts: First, electric focusing: a electronic focusing assembly is designed based on electron motion characteristics of the MCP output end to converge the disperse electron beam to facilitate receiving of first amplifier; Second, detector: in order to meet requirements in specific environment, a single-channel electron multiplier(CEM) is used as the electronic detector for the detection system; Third, hardware circuit: in this part, a preamplifier current and filter circuit according to the output characteristics of CEM.Software simulation and experimental verification method is used to detect the stream of electrons at nA level and verify the feasibility of low current detection system proposed in this paper. The experiment results show that, the design scheme in this paper realizes the purpose of accurate detection of low current and lays the foundation for accurate detection of signal-to-noise ratio of MCP.