The operation of GFIS involves several key steps: 1. A sharp needle, often less than 100 nanometers in diameter, is placed in a high electric field. 2. Gas atoms, such as helium or neon, are introduced near the needle tip. 3. The strong electric field ionizes these gas atoms, creating positive ions. 4. These ions are then accelerated and focused into a beam, which can be directed at a target for various applications.
