A NEW ION DETECTOR ARRAY AND DIGITAL-SIGNAL-PROCESSOR-BASED INTERFACE

A new one-dimensional ion detector array on a silicon chip has been de veloped for use in mass spectrometry. It is much smaller and simpler t han electro-optical arrays currently in use and in addition has a high er resolution and a zero noise level. The array consists of a one-dime nsional array of metal strips (electrodes) with a pitch of 25 mum on t he top surface of a silicon chip, each electrode having its own charge pulse sensor, 8-bit counter and control/interface circuitry. The chip is mounted on a ceramic substrate and is preceded by a micro-channel plate electron multiplier. Chips are butted to give a longer array. Te st results show a stable operating region. A digital-signal-processor- based interface is described, which controls the mode of operation and reads the accumulated array data at the maximum rate to avoid counter overflow.