Picosecond photocathode electron source (transmission mode). The dashed line represents a typical trajectory for the pulse envelope. Inset: cross section of a cylindrical pulse of length and radius .
Radius of the transverse profile of electron pulses at a distance of from the pinhole, as a function of the laser beam radius . Measurements (×) and calculations (solid line) with a photocathode current , except for the left points × and ◻ : . Dashed line: effect of the diverging lens and initial kinetic energy without space-charge effects. and .
Radius of the transverse profile of electron pulses at a distance of from the pinhole, as a function of the acceleration voltage, for two different laser beam radii. The current-voltage conditions are the same for measurements (×) and calculations (◻): , , , and for (a) and , , , and for (b).
Calculated pulse radius (a) and pulse duration (b) of electron pulses at the end of the extraction region, as a function of the initial pulse width . Acceleration voltage: ; distance: ; current: .
Simulation of the trajectories of electron pulses in the photocathode-to-mesh region for different initial pulse radii (, , and ).
Calculation of the kinetic-energy spread (solid line: longitudinal; dashed line: transverse) as a function of the initial pulse width (, , and ).
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