SINGLE-PARTICLE DETECTOR SYSTEM FOR HIGH-RESOLUTION TIME MEASUREMENTS

A compact detector system for single particles (e.g. for time of flight mass spectrometry) with an input area of 27 mm in diameter and over all height of 20 mm bas been developed using a two-stage chevron microchannel plate (MCP) and a high speed trigger circuit. A special anode configuration with a thickfilm ceramic provides up to 7kV insulation between the anode of the MCP and the following electronics as well as wide bandwidth without ringing. Additionally the mean position information of the particles is available by dividing the anode into 16 segments. The average current for each segment is monitored. The high speed trigger circuit is directly mounted into the detector system. The MCP response with its wide amplitude variation is converted into an ECL level signal. The power dissipation is less than 300mW. A time resolution of 500ps and a dead time less than 3ns are achieved.