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The Center for Bright Beams, A National Science Foundation Science and Technology Center

Stochastic space charge algorithm

a light orang oval above a box with dots with arrows pointing in many directions within it
By simulating high brightness photocathode beamlines, we can determine the effects of disorder induced heating

Electrical repulsion can blow up electron beams, an effect known as space charge repulsion. Space charge is particularly challenging for intense beams produced by high performance photocathodes, such as those under development at CBB. Till now, simulating space charge has been difficult because tracking the millions of electrons is computationally prohibitive, while simplifications tend to sacrifice important features. CBB has developed a new algorithm that captures the point-like nature of electrons in their interactions with the photocathode and each other, but with greatly reduced CPU demands. The new technique will be key as CBB optimizes beamlines to take maximal advantage of the new photocathodes in order to achieve bright beams.