Numerical analysis of electron optical system with microchannel plate

Abstract

This paper describes a numerical development of image converters and intensifiers which incorporate an inverting electron optical system (EOS) and a microchannel plate (MCP) as an amplifier. The numerical design of the system includes calculation of the electrostatic field in the device, trajectories of electrons emitted from a photocathode, and determination of the modulation-transfer-function (MTF) which gives the objective estimation for the image quality.Results of the numerical experiments are shown, and the EOS with optimized characteristics is developed. It provides the nearly flat image surface, determines the position of the surface of the best focus, minimizes the image distortion and reduces a noise factor of the MCP.

Mathematical and Computer Simulation of Visual Acuity in Imaging Devices

“…Such calculations are based on numerical calculation of the field distribution inside the device and the channel, trajectories of the photo-and secondary electrons [7].…”

“…3 shows the computational results of the potential distribution (given by the equipotential lines) in the cross-section of the EOS. An electrostatic lens, formed by MCP-screen field penetration into channels, at the output of a channel has a significant influence on the electron trajectories and the spatial resolution [7]. The potential distribution in the field of the lens depends on the field intensity in the MCP-screen gap, the channel diameter, and the sputtering depth of the contact layer at the channel output.…”

“…In the cylindrical coordinate system, equations of motion of electrons can be written as: (4) is solved by the Runge-Kutta method for the electron motion inside the EOS of the device, and in the area of the inhomogeneous electrostatic field of the channel multiplier. The strengths of the electrostatic field at the exit of a single channel and inside the EOS are calculated using different interpolating polynomials [7]. Fig.…”

“…The MTF of the overall system, at a given spatial frequency, is the product of the MTFs of the elements [2], [3], [7]. Consequently, to evaluate the total MTF of the imaging system with a micro-channel plate, the MTFs of EOS and MCP-screen system should be determined.…”

“…where M and D are the mean gain and variance of the distribution at the output of the channel [5], [7]. Using the theorems about serial and parallel amplification stages, expressions for calculating the noise factor of the image detector can be obtained.…”