Detector · 3 / 3
The simplest detector: catch ions, measure the current directly
A Faraday cup is a deep metal cup that catches ions directly. As ions land and are neutralized, they drive a current through the connected wire — a current you can measure directly. The more ions arrive, the larger the current. There is no multiplication.
Adjust the ion beam and watch the meter and the current trace respond.
Because it simply collects charge, a Faraday cup is extremely stable, accurate, and robust — often used as a reference and for measuring strong ion beams. The trade-off is sensitivity: it is slower and cannot register single ions the way an electron multiplier or MCP can.