LOW-NOISE WIDEBAND PREAMPLIFIER FOR FOURIER TRANSFORM MASS SPECTROMETRY

摘要

An ion cyclotron resonance (ICR) mass spectrometer includes an ICR cell having detection plates generating a detection current signal, detection circuitry generating a digital signal from the detection current signal, and a processor calculating a mass spectrum from the digital signal, wherein the detection circuitry includes a preamplifier having a differential pair of input junction field effect transistors (JFETs) receiving the detection current signal from the ICR cell, a pair of second JFETs in cascode configuration with the input JFETs, and an analog to digital converter generating the digital signal from a differential voltage signal generated by the second JFETs.