Gain of a microchannel plate for low-energy positive ions

Gain characteristics of a microchannel plate (MCP) for positive ions with energy of 100 eV have been measured under two different operation modes: the reflection mode and the conventional transmission one. The reflection mode produces an automatic preacceleration effect on incident ions penetrating into the microchannels and therefore increases the overall gain remarkably. When an MCP with zero bias angle was used, the modal gain increased by about two orders of magnitude compared with the transmission mode and the detection efficiency would be acceptable for practical use. The reflection mode is potentially useful for the detection of low-energy positive ions. (author)