Gain model for a microchannel plate operated in the reflection mode for detecting low-energy positive ions

A simplified model is presented to explain the gain characteristics of a microchannel plate (MCP) operated in the reflection mode for detecting low-energy positive ions. Analysis, taking into account an automatic preacceleration effect of the potential applied across a MCP on incident ions penetrating into the microchannels, can lead to high gain performance in this operation mode. The resultant calculated gain-applied potential and gain-incident ion energy curves fit well to the data reported previously. It is also shown that the gain is almost entirely determined by the transmissibility of incident ions through the microchannels toward the backplate