Numerical and analytical models of gain saturation in microchannel plate devices

We present and compared two different approaches for modelling microchannel plate (MCP) devices in regime of gain saturation. In our numerical model an MCP is described as a ladder network of interacting R and C lumped elements. The Kirchhoff equations of the network are coupled to a gain equation describing the amplification of input pulses as they progress into the microchannels. This non-linear system can be solved numerically and can be included into a best-fit algorithm capable of determining the model parameters from experimental data. An alternative analytical model was developed assuming a simplified network and describing pulse amplification and wall charge replenishment with a pair of differential equations. In this way, simpler analytical equations are found that describe an MCP in a broad range of operating conditions. Measurements on a Z-stack MCP photomultiplier showed that the numerical model provides a fairly accurate description of the MCP in pulse mode. The analytical model, although less accurate, is more suited to best-fit algorithms, allowing a remarkable reduction of computer time and of convergence problems.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.