3.8.1.2
Beta-minus is an electron emitted when a neutron converts to a proton
Nuclear Structure & Radiation — AQA A-Level Physics
Key Definition
Beta-minus particle — A high-energy electron emitted from the nucleus when a neutron converts to a proton. Notation: ⁰₋₁β. Accompanied by an anti-electron neutrino.
- Emitted by nuclei with too many neutrons (neutron-rich, left of stability line).
- Moderately ionising — ~100 ion pairs per cm in air.
- Moderately penetrating — range 20 cm to 3 m in air. Stopped by a few mm of aluminium.
- Deflected through large angles in electric and magnetic fields (towards the positive plate).
- Much less mass than alpha, so deflects more for a given field strength.