Mechanism of Fixed Pattern Noise of Micro-Channel Plate Focusing on Cross-Section of Single Channel

Fixed Pattern Noise (FPN) of MCP significantly influences resolution and clarity of detected images. This investigation focuses on the cross-section of single channel to clarify the formation mechanism of FPN. The cross-section is obtained by microscopic observation of circular MCP samples, and the FPN is measured. Circular and defective cross-sections, as well as regular polygonal and rectangular cross-sections are modeled. The shortest distance through the center of the cross-section is proposed as an index to characterize length-to-diameter ratio(L/D). The gain, escape dynamics of multiplied electrons from the output end and electron beam spot shape on phosphor screen are simulated. Results indicate that defective circulars are equal in cross-sectional area. As the bias voltage increases, the electron gain increases. The higher the roundness and the shortest distance through the center of cross-section, the higher the gain and the spreading angle of emitted electron beam. The electron emission trajectory at the output end of MCP and beam spot shape on phosphor screen varies with the cross-section. Deformation of boundary micropores in the multi-fiber decreases gain, resulting in dark-grid fixed pattern noise. With higher bias voltage, the L/D of boundary micropores increases gain, leading to bright-grid fixed pattern noise.