A multichannel plate (MCP) detector is very similar in operation to an electron multiplier, but whereas the electron multiplier has a single channel of amplification, a MCP is compromised of numerous parallel channels that are distributed across a plane.  As such, the MCP can provide spatial information that the electron multiplier can not.  This spatial information is crucial in certain types of mass analyzers that spread the ions in space based on the mass-to-charge ratio, namely electric and magnetic sectors.  For mass analyzers that separate ions in time based on mass-to-charge ratio (e.g. ion traps, mass filters, time-of-flight, etc.), the spatial information provided by an MCP has limited utility.