Single electron detection and spectroscopy via relativistic cyclotron radiation

Understand

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation.

• Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904.
• Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly.
• Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer.