Understanding electron beam halos

Jefferson lab physicist aims to develop large dynamic range diagnostics for electron linacs

Christine Herman (FNAL) | 8 September 2011

Some physicists joke about electrons, saying that you cannot collimate them, you can only make them angry. Collimation is the removal of low-intensity, high-amplitude particles from a particle beam, typically by absorption into a metal. These unwanted particles, which make up what’s known as the halo, could cause high backgrounds in collision data and wreak […]

Pushing the limits with high-voltage electron guns

Jefferson Lab’s electron gun group explores new designs for spin-polarised photoelectron guns

Christine Herman (FNAL) | 21 July 2011

Opposites attract and like charges repel. This simple phenomenon explains why electron beams spread out over space and time, much to the dismay of physicists who need tight particle beams for collision experiments. To counter this phenomenon, known as space charge-induced emittance growth, the electron gun group at Jefferson Lab in the US is pushing […]