Abstract

We present a novel, compact electron source for a high-temporal-resolution ultrafast electron diffraction (UED) instrument. The source, which employs field-enhancement at a pin-shaped photocathode to allow driving by a solid-state, rack-mountable 10W-average power, 10 kW peak power S-band RF amplifier, can produce 180 keV electron bunches of 100 fC charge that compress via velocity bunching down to 100 fs a distance of 8 cm from the photocathode. A solenoid, following the gun, focuses the electron beam, resulting in a low transverse emittance of 0.1 mm mrad. These specifications make the photogun an ideal source to build a high brightness UED setup with performance surpassing traditional DC-gun-based setups.

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